The possible overlap and differences of structural language difficulties exhibited by patients with autism spectrum disorder (ASD) and specific developmental language impairment (SDLI) have attracted the attention of numerous researchers over the years (e.g., Lindgren et al. 2009; Fortunato-Tavares et al. 2015; Creemers and Schaeffer, 2016; Chomsky et al. 2019). Many of these studies have focused on the language production and language comprehension deficits of ASD and SDLI among English-speaking patients. Language comprehension calls for various sub-skills, including distinguishing between comprehension flaws, identifying language, comprehending complicated phrases, developing verbal thinking and recalling word sequences (Bishop 2014).

Syntactic movement, a subject explored in specific syntactic theories, addresses the problem of discontinuities. It was initially introduced by structuralists and was characterized as encompassing the displacement or rearrangement of constituents. In certain instances, constituents seem to have been shifted from their original positions to obtain essential interpretive characteristics. The concept of movement is a topic of debate and is closely linked to transformational theories of syntax, such as transformational grammar and binding theory (Ryding 2005).

As Simpson (2000) detailed, the Wh-movement is a linguistic phenomenon related to language construction that turns basic phrases into questions (i.e., creating syntactic dependencies using interrogative words resulting in wh-questions). Children are regularly exposed to such sentence structures in their everyday lives. The ability to identify and recognize structures that have undergone syntactic movements (e.g., the Wh-movement of moving a phrase to the beginning of a clause; to spec-CP) is considered a crucial linguistic skill for language development. Difficulties in processing syntactic dependencies are the most telling sign of a syntactic deficit among children and adults (e.g., Friedmann and Novogrodsky 2004; Novogrodsky and Friedmann 2006; Levy and Friedmann 2009). Identifying whether a member of the ASD or SDLI group has a language impairment is even more challenging when the words used to construct a question are rearranged and an interrogative word is added at the beginning of the phrase.

The assertion that the complexity of these structures can be clarified by including Wh-movement from the subject position is supported by the challenges in comprehending questions with Wh-movement and the performance in processing simple sentences that lack Wh-movement (Friedmann 2002). The theme does not come after the verb in questions like “Which boy (did) the grandfather draw?” but instead comes first in the sentence. In these situations, the moved element’s trace is given the thematic role by the verb, and the thematic role is then transmitted from the trace to the moved element via a chain that joins the trace and the moved element in its new location (Wright 2022).

According to Friedmann and Haddad-Hanna (2014), understanding multiple syntactic levels can be particularly challenging for those with language impairment. Hearing loss involving 24 Palestinian Arabic speakers with oral training (21 had mild to profound binaural hearing loss, and 3 had monaural hearing loss). Ten structures created by Wh-movement were evaluated. The structures included three varieties of wh-questions, five relative clause forms, two tropicalised structure types and two basic sentence types. Using a sentence-picture matching task, their first experiment examined the relationships between the topic and object. A photo selection task was used in their second trial to assess subject and object questions. Their third trial used comprehension questions to assess relatives of the subject and object. Their fourth experiment used a reading and paraphrasing task to examine subject and object relatives and tropicalised sentences.

As Rahmeh et al. (2021) discussed, in Arabic, phrases and questions follow the Subject-Verb-Object (SVO) and Verb-Subject-Object (VSO). The inquiry words can be used to ask about a subject or an object. Arabic-speaking children with ASD and SDLI need to identify and track the trail of the sentence structure, which involves moving the noun phrase of interest to the beginning of the sentence and replacing it with a question term when converting a simple sentence into a question.

Mayberry and Lock (2003) argued that age has no bearing on language acquisition, as the comprehension issues that first appeared in sentence structures acquired before age 9 remained problematic until age 21. The issue persists even though the phrases in the Arabic-speaking children’s feedback contain Wh-movement. The prevalence of phrases that involve Wh-movement at such a high rate emphasizes the importance for people with hearing loss to be aware of their condition. According to Friedmann and Szterman (2006), some children who used hearing aids before 8 months could comprehend sentences with Wh-movement comparable to hearing children. Nabelek and Pickett (1974) suggested that all subjects with binaural hearing impairment may have performed poorly owing their hearing aids. The contestants’ challenge in understanding these patterns provides substantial evidence for vacuous movement in subject inquiries and simple sentences devoid of Wh-movement. Their difficulty can be explained if these structures contain Wh-movement from the subject position (Friedmann and Novogrodsky 2007).

Goodwin et al. (2012) discussed that children diagnosed with autism display a delayed acquisition of comprehension skills regarding wh-questions compared with typically developing children. However, their overall language development remains similar. Both groups refrain from producing wh-questions until they understand the underlying grammatical rules. Consequently, children with autism appear to process wh-questions in a manner akin to their typically developing counterparts, albeit at a later stage of development.

Lindgren et al. (2009) proposed that autism has an early childhood onset and can affect the comprehension of syntax and phonological abilities. Speech difficulties resulting from impairments may arise from internal or external factors, such as autism or brain injury, which impact the ability to produce sounds and comprehend words. As defined by Foley (2009), Syntax encompasses the concepts and processes governing sentence structures in each language. It also refers to studying the principles and parameters that organize sentences (Chomsky and Lightfoot 2002).

The influence of autism on syntactic development has some surrounding controversy. The syntactic abilities of individuals with autism, compared to other language domains or non-autistic peers with developmental delays, do not appear to be impaired (e.g., Joseph et al. 2002; Rapin and Dunn 2003). Syntactic development involves the acquisition of rules used to combine words and construct sentences and represents the process through which children learn these rules (Eigsti et al. 2011).

Friedmann and Haddad-Hanna (2014) examined whether people with hearing loss may still comprehend some sentences without significant early language exposure. The researchers looked at this issue for adults and adolescents with hearing impairments who were native speakers of Palestinian Arabic. They concentrated on Wh-movement-filled sentences. Given that the SVO basic word order is the same in Palestinian Arabic and English, various word orders can be created by moving one of the phrases to a different position in the sentence. According to research, children with hearing impairments who spoke Hebrew or Palestinian Arabic showed significant problems with object-relative clauses and which-object questions. The result implies that the problem was brought on by object-relatives and object inquiries rather than the embedding in relative phrases, which is thought to be the cause of the understanding deficits.

Witecy and Penke (2017) found that children with ASD had more trouble using accusative language than their SDLI counterparts who spoke English or French. The researcher looked at the language performance of children with ASD to establish their linguistic ability and look for the presence of different subgroups within the larger ASD group. To help speech therapists and pathologists in autism centers develop better teaching tools. This study advocated the advantages of using children with ASD’s spontaneous language to assess their lexical and grammatical skills. It showed that several subgroups of children with ASD differ depending on linguistic and cognitive ability.

As discussed by Friedmann and Costa (2011), the movement in the word order in these sentences might constitute difficulty and complexity in the comprehension of the sentences that include the movement. In Arabic, sentence and question structures typically follow SVO and VSO patterns, respectively, and questions can be formed for subjects and objects using question words. Transforming a simple sentence into a question requires moving the noun phrase being inquired about to the beginning of the sentence and replacing it with one of the question words. This movement challenges children with ASD and SDLI to understand questions. Children with language impairments may encounter difficulties in comprehending questions derived through Wh-movement because they need to identify the trace of the sentence. This difficulty is caused by the notion move requiring more processing related to the mental lexicon.

Movement introduces additional complexity compared with simple sentences. In each sentence, the verb assigns thematic roles to the noun phrases. Typically, the first noun phrase takes on the agent role, whereas the second noun phrase assumes the theme role. When one of these noun phrases undergoes movement, assigning thematic roles becomes more intricate. The verb assigns the thematic role to the “trace” left behind by the moved noun phrase, and then this role is transferred to the noun phrase in its new position through a chain. The listener needs to know the presence of a trace and its location to comprehend a sentence involving Wh-movement. They must assign the correct thematic function from the verb to the trace and connect the trace through the chain to the relocated noun phrase. Failure in any of these steps makes understanding the sentence’s thematic structure challenging, including identifying the subject and object. This understanding is crucial for comprehending sentences involving Wh-movement, as proposed by Elman (1995).

In the cohort of children with ASD, Durrleman et al. (2016) revealed a connection between the children’s age, nonverbal abilities and their scores on the syntactic complexity measure. In contrast to the typical development observed in the TD group, where performance progressed in line with age and nonverbal abilities, which were interrelated, the performance of ASD children depended solely on their nonverbal abilities, without any correlation to age.

The correlation between nonverbal abilities and the scores of ASD children on the syntactic complexity measure highlights the significance of nonverbal abilities in the development of syntactic complexity. The absence of a correlation between age and the scores of ASD children on the syntactic complexity measure, combined with the lack of a correlation between age and nonverbal abilities, indicates a discrepancy between age and nonverbal abilities concerning syntactic complexity. The progression of syntactic complexity in children with ASD does not align with the gradual relationship to age observed in typically developing children (Novogrodsky 2015; Cain et al. 2005; Loucas et al. 2013).

The primary objective of this research is to explore how children with ASD and SDLI comprehend wh-questions in subject and object structures and to compare their comprehension abilities with typically developing children. The study aims to identify any distinct comprehension difficulties experienced by 6–8 years old children with ASD and compare them with those exhibited by SDLI children. This study is particularly crucial because of a lack of studies investigating the comprehension of wh-questions among Jordanian children who have ASD and developmental language impairment and use Jordanian Arabic as their native language.



The participants were three groups of children divided into 15 children with ASD, 15 with SDLI, and 15 TD children as the control group. Each group consisted of children aged 6–8, means and standard deviations of the ages were 7.20 (0.77) years for the ASD group, 6.80 (0.94) years for the SDLI group and 7.27 (0.70) years for the TD group as the control group.

All 15 participants in the ASD group for Tasks 1 and 2 included 15 Jordanian Arabic-speaking children with ASD (8 males and 7 females). Mean and standard deviation of the ages were 7.20 (0.77). All the children attended the autism center in Amman, Jordan, and all spoke Jordanian Arabic as their native language. All the ASD participants had been diagnosed with ASD by a pediatric psychiatrist before the study and registered in 33 center as ASD children. No participant was diagnosed as having “low functioning” autism, according to the American Psychiatric Association (2000).

The participants in the SDLI group who participated in Tasks 1 and 2 included 15 Jordanian Arabic-speaking children (11 males and 4 females). Mean and standard deviation of the ages were 6.80 (0.94). All the children attended regular classes in second to fourth grade in regular schools. All the participants met the exclusionary criteria for SDLI (Leonard 2014) as they had no hearing impairments, no recent episodes of otitis media, no abnormalities of oral structure or problems in oral function. They showed no evidence of obvious neurological impairment or impaired neurological development. They had no symptoms of impaired reciprocal social interaction or restriction of activities that are typical of autism. With respect to the inclusion criterion, all the participants in the SDLI group had been diagnosed with SDLI before the study through clinical tests conducted by speech-language pathologists and educational specialists in the school based on reading comprehension assessments and non-standardized tests used in clinics.

The control group in Tasks 1 and 2 included 15 Jordanian Arabic-speaking children (10 males and 5 females). The mean and standard deviation of the ages were 7.27 (0.70). All TD participants who represented the control group had no neurological development difficulties. They were students in public school, with Jordanian Arabic as their native language.


Design of the study

The research design encompasses the comprehensive strategy chosen to address the research problem effectively, integrating various study components coherently and logically. It serves as a blueprint for data collection, measurement and analysis. Each participant’s performance was analyzed to assess their understanding of questions generated through Wh-movement. By examining different sentence structures, this study investigated whether language difficulties in children with ASD can be categorized as SDLI language difficulties in the Jordanian Arabic language.

If the language difficulties experienced by children with ASD resemble those observed in the SDLI group, we anticipated observing similar patterns in comprehension performance. Specifically, ASD participants should exhibit similar distinctions between impaired and intact structures, as seen in SDLI participants. Additionally, we would expect ASD participants to make comparable comprehension difficulties to those made by children with SDLI.

Sentences of Wh-questions

This study uses an adapted scale from the classic work of Friedmann and Novogrodsky (2011) to examine the comprehension of wh-questions. The process of modifying the figures for the final instrument included validation, translation and pilot testing of the figures. After got a response and permission from the relevant departments, the researcher collected the tools from the relevant research. The scale was adapted into Arabic from the English language since the current respondents of the study are Jordanian Arabic speakers who are not proficient in English.

Three steps were taken to ensure the validity of this translation process. Firstly, two experienced Arabic writers from translation centers in Jordan translated the figures into Arabic. Secondly, the Arabic-translated figures were presented to three bilingual experts. Altogether, the accuracy of the translations was checked by these five experts. Lastly, the figures in Arabic were given to seven Arabic-speaking postgraduate students and ten school children to examine whether they could comprehend the aims and meaning of the figures. All five experts validated the accuracy of the instruments.

Sample size and sample selection

This study used probability sampling, which utilizes random sampling techniques and principles to create a sample, having given all members of a population an equal chance of being selected. It is the purest and clearest probability sampling design and strategy.

Binary task

The researcher used the same procedure that Friedmann and Novogrodsky (2011) used to collect the performance of who and which (subject and object) questions. The researcher showed a page including two pictures and asked questions while the participants looked at the pages. The participants were asked to point to the picture that matched the question’s true answer. The researcher then tested participants individually without any limit, and the sessions were 40–60 min. The researcher repeated items when the participant requested.

The comprehension of wh-questions was tested for participants using two binary picture-selection tasks. Task 1 included pictures with two figures (Fig. 1), and Task 2 (Fig. 2) included three figures. The researcher asked a question while the participant looked at a page with two pictures, presented one above the other. The participants were requested to point to the picture that matched the question. Each participant was tested individually in a quiet room with no time limit during testing. The researcher repeated every item as many times as the participant requested.

Fig. 1: An example for a picture used in the two-figure task.
figure 1

Reproduced with permission of Elsevier license number: 502050907717.

Fig. 2: An example for a picture used in the three-figures task.
figure 2

Reproduced with permission of Elsevier license number: 5502050907717.

Two figures were shown to the participants. Figure 1 showed the role matched the sentence in the first one, whereas the roles are reversed in the second. Questions were asked to each participant: 20 “who” subject and object questions and 20 “which” subject and object questions. Some examples are as follows: (Who subject question)- (Who has touched the other? /Meen Ely Darab El-thany? /), (Which subject question)- (Which one touched the other? /Aya Wahed Ely Darab El-thany? /), (Who object question)- (Who has been touched? / Meen Ely Endarab? /) and (Which object question)- (Which one has been touched? /Aya Wahad Ely Endarab? /), see Fig. 1.

In the second task, the researcher used three different figures, as shown in Fig. 2, to investigate the comprehension regarding wh-questions with three different figures. The participants asked to find the right answer between two completely different figures. This task had 40 questions, including 20 who and 20 which questions of each type (subject and object. Examples are as follows: (Who subject question)- (Who is taking picture for the other? /Meen Ely Besawer El-thany? /), (Which subject question)- (Which one took a picture for the other/Aya Wahed Ely Am Ytsawr? /), (Who object question)- (Who has been captured a picture? /Meen Ely Tsawer? /) and (Which object question)- (Which one has looking for a picture? / Aya Wahad Ely Betsawar? /), see Fig. 2. The questions were asked randomly and ordered and presented with 20 pictures. The questions were ordered randomly and presented in two sessions of 20 questions. The participants saw 20 pairs of pictures. Each picture had two question types.


Due to hypothesis testing, analysis of variance (one-way ANOVA) was extracted to explore the difference in the levels of comprehension of “Who” and “Which” subject-object questions in both tasks due to each group.

Table 1 shows that there were statistically significant differences in the levels of comprehension in both tasks, two-figures task, and three-figures task in each group (0.00). (Scheffe) test results were extracted for both tasks in a Who Subject questions between means of both ASD, SDLI and control group.

Table 1 Results of one-way ANOVA and Scheffe test in the levels of comprehension of “who and which” object and subject questions due to each group.

For H1, that focuses on “Who subject” questions, it can be observed that the ASD group had a mean score of 1.27 in the two-figure tasks and 1.87 in the three-figure tasks, which were significantly lower than the SDLI and Control groups. This indicates that children with ASD have more difficulty with comprehending “Who subject” questions compared to the other groups. In H2, examining “Who object” questions, the ASD group had lower mean scores (0.20 in two-figure tasks and 0.67 in three-figure tasks) compared to the SDLI and Control groups. These results suggest that children with ASD faced difficulties in comprehending “Who object” questions, particularly in the three-figure tasks. Moving on to H3, which focuses on “Which subject” questions, ASD group obtained significantly lower scores (0.00 in two-figure tasks and 0.53 in three-figure tasks) compared to the SDLI and Control groups. Lastly, for H4, examining “Which object” questions, the ASD group had lower mean scores (0.00 in two-figure tasks and 0.13 in three-figure tasks) compared to the SDLI and Control groups.

In summary, the outcomes consistently indicate that ASD children obtained lower scores in all question types and tasks when compared to the SDLI and Control groups. These results imply that children in all tested groups may encounter difficulties in comprehending “Which” questions, especially in more intricate tasks that include three figures.


This discussion presents the difference between questions that are difficult to understand and those that are easy to understand. Numerous academics have indicated that who object of the research question has been incompletely understood in its current form, including Friedmann and Szterman (2010, 2011). Recognizing that not every argument that is crossed with another does not help to understand is an adjustment that can help paint a clearer picture.

The study used ANOVA to determine the level of comprehension and the number of correct answers for three groups (children with ASD, children with SDLI and TD children from Jordan aged between 6 and 8 years). The study subjects were asked to identify the subject and the object of syntactical wh-questions. The study conducted one-way repeated measures ANOVA to examine the significance of differences in the children’s performance in the different groups for different types of wh-questions (who subject, who object, which subject and which object) in two-figure and three-figure tasks.

The ASD group performed poorly for all types of questions, and the group performed least well among the three groups in all types. The answers of the Jordanian children with ASD were mostly incorrect. The study’s findings show that “which” questions constitute a problem for children with ASD and children with SDLI because they require a longer movement than who questions. “Who” questions are easier for all groups to understand because they do not require a longer movement. Levels of comprehension among the ASD, SDLI and TD groups statistical analysis of the results suggests that most children with ASD gave wrong answers compared with SDLI and TD groups. Similarly, the results suggest the poor performance of the children with ASD for different types of wh-questions that vary from one question to another. To put it differently, which questions constitute major problems for children with ASD as opposed to who questions. The 60-ASD children group had close levels of comprehension in the Figure-2 and -3 tasks. SDLI’s performance was better for who subject, who object and which subject questions in the first task compared with the second task. In respect of who subject questions, the children with SDLI showed a significant difference in performance in both tasks. The children with SDLI and TD children provided more correct answers than those with ASD. However, the TD group’s answers were better than those of the other groups. The differences between the children with SDLI and the TD children were minor in the first task and major in the second task. TD children provided the correct answers for most of the wh-questions. The reason for the poor performance of children with ASD and SDLI may be related to their mental abilities in terms of connecting, analyzing and differentiating the subject from the object (Rice et al. 2005).

Overall, the types of questions played a major role in their comprehension, which had implications for their performance. Another interesting finding was that the number of correct answers and the level of comprehension for the children with SDLI was better than for the children with ASD. Another important finding was that the existence of three characters posed a problem for both the children with ASD and the children with SDLI, meaning that the students were unable to point out the correct answers for wh-questions because they were confused when there were more than two characters, even though the children with ASD got some correct answers in the three-figures task. The study attributes the poor performance of the children with ASD and SDLI to the following reasons: their syntactic difficulties, their delayed mental development hindering their comprehension, and their lack of exposure affecting their comprehension of Wh-movement in general and object questions in particular. The study suggests that children with SDLI have difficulty comprehending sentences that include syntactic movement at the beginning of the sentence. Children with SDLI have a syntactic deficit, and considerable difficulty with structures derived by Wh-movement, and their mental disability may hinder their comprehension of wh-questions. The study believes that children with ASD have limited background knowledge, which would impact the accuracy or correctness of their responses, the syntactic delay that autistic children have, and their limited cognitive abilities (Szterman and Friedmann 2003).

Several factors can account for the high performance of individuals with ASD in the three-figure task compared with the two-figure tasks. One possible explanation is that the inclusion of an additional figure in the three-figure task provides supplementary visual cues and contextual information, facilitating a better understanding and processing of the task requirements among ASD participants. The presence of an extra figure can act as a beneficial reference point, aiding in establishing connections and associations between the figures. Furthermore, the heightened complexity of the three-figure task can engage higher-order cognitive processes, such as pattern recognition, spatial reasoning and working memory. ASD individuals often exhibit strength patterns in cognitive domains related to visual-spatial processing (Fernandez 2020). ‏This advantage may contribute to their enhanced performance in tasks involving multiple visual elements or necessitating spatial manipulation. Moreover, the inclusion of three figures in the task provides ASD participants with more opportunities to employ their preferred cognitive strategies and leverage their distinctive information processing styles. Some individuals with ASD display a detail-focused processing style, whereby they concentrate on specific aspects of stimuli or tasks, as discussed in Happé and Frith (2006). Within the context of the three-figures task, this detail-oriented approach enables these individuals to discern subtle patterns, relationships or disparities among the figures, thereby leading to improved performance. The explanations are speculative and may not universally apply to all individuals with ASD. Performance levels can greatly vary among individuals with ASD, given their unique strengths, challenges and cognitive profiles. Therefore, further research encompassing a larger sample size and employing diverse cognitive measures is needed to explore and validate these explanations.

Moreover, Durrleman et al. (2016) provided evidence that movement, intervention and feature similarity collectively contribute to children’s sentence comprehension, albeit with varying degrees of influence depending on their linguistic development. Even with a difference in features between the moved element and the intervener, the presence of intervention effects suggests that configurational intervention has its own independent role of featural similarity. However, the effect of intervention is amplified proportionally to the degree of feature overlap; the greater the overlap, the more the intervener disrupts the dependency.

The children with ASD were unable to answer “which” subject and “which” object questions in the two-figure task. However, their performance on which questions improved slightly in the three-figure task. The reason could be that the children with ASD became familiar with each question. Thus, their level and performance increased in the three-figure task. The children’s SDLI performance was higher in the two-figure task than in the three-figure task. Possibly, which questions in the three-figure task became harder, leading to their lower level of performance in the second task. “Which” questions could be problematic among ASD and SDLI groups. This finding goes in line with the study conducted by Vogel (1974) that examined the syntactic abilities between TD children and children with ASD and deduced that the TD children performed much better than the children with ASD. The findings of this study suggest that the comprehension of wh-questions is significantly influenced by the types of questions used. Specifically, “which” object questions present challenges for children with ASD, SDLI and TD children. This difficulty can be attributed to the fact that “which” questions require greater movement than “who” questions. The extended movement associated with “which” questions increases comprehension time. Regarding the picture selection of numbers, the results indicate the existence of varying degrees of comprehension impairment between the two-figure task and the three-figure task. Both children with ASD and SDLI experience difficulties when faced with three characters. Their limited comprehension abilities may be attributed to their inability to focus on the correct response, particularly when they are presented with the choice between two or three different characters, leading to confusion.

This study’s significance lies in its examination of the challenges of identifying syntactical wh-subject and object questions among children with mental disabilities, especially object questions. Abu Bakar et al. (2022) argued that linguists and therapists should be able to gain a solid background of the differences between impaired and typically-developing children in comprehending wh-questions. The analysis revealed that the children with ASD’s correct answers to the wh-questions were unremarkable. In other words, the correct answers of the children with ASD were fewer compared with the other groups. As illustrated in the above results, the types of questions play a major role in their comprehension, which impacts their performance. However, their comprehension of who object and who subject questions was better in the first task compared with the second task. The analysis revealed that the children with SDLI’s correct answers to the wh-questions were unstable. Their answers were better than those of the ASD group. However, their comprehension of wh-questions was better in the two-figure task compared with the three-figure task. For the who subject questions, the children with SDLI showed significant variation in performance between the two tasks. Their understanding of who questions was better than for which questions, particularly object questions, which aligns with Friedmann and Haddad-Hanna’s (2014) findings regarding the difficulties that Palestinian Arabic-speaking children have in understanding which object questions. TD children group successful performance and comprehension on the wh-questions was of the highest proportion compared with the children with ASD and SDLI. Most significantly, the type of questions asked had no impact on their comprehension or their performance. This study is more in line with Eigsti et al.’s (2007) study regarding syntactic impairment.


Given that comprehension only fails when the arguments are comparable or when they are of the same type, educational ramifications vary. However, one does not block the other when the two arguments are different, such as when one is referential and the other is non-referential. According to this definition, the moving term “who” is nonreferentiality in who object questions (such as “Who did father draw?”), whereas the intervening NP (father) is referential. Given that the intervener is not of the same type as the moved “who” phrase, it does not prevent the “who” phrase from being given a thematic role. In which questions, the moved phrase is referential (“which boy?” for example). Thus, when the intervening element is referential as well (father), it belongs to the same type as the which phrase and prevents the moved which phrase from being given the thematic role. Thus, children with ASD and SDLI have more trouble with which questions than they do with who questions. By stepping back, this generalization can be used to explain the current results on wh-questions and a list of structural impairments in children with ASD and SDLI, as well as structural improvements. The conclusions of this study will open the door for more related studies. Firstly, these studies should encompass a variety of wh-questions to reveal the level of comprehension of these questions between children with SDLI and children with ASD. Secondly, it would be useful to conduct a contrastive study to examine the level of comprehension of syntactical wh-questions between younger and older individuals with ASD and SDLI.