This study focuses on the linguistic abilities of preschool children in the autistic spectrum. The objectives were to identify and evaluate the approaches to language in the most frequently used therapeutic approaches for ASD in the speech therapy practice, in a sample collected in Rio de Janeiro, and to propose an instrument to assess ADS children s language skills, by tracking specific difficulties in comprehension tasks. The instrument aims to evaluate syntactic structures (simple sentences varying in transitivity and tense/aspect of the verb; interrogative sentences; coordinate sentences; completive clauses; and relative clauses), morphosyntactic distinctions (gender and grammatical number) and aspects pertaining to the syntax-semantic interface (reflexive and referential pronouns), by avoiding the cost of thematic reversibility. In addition, reversible sentences were included to continue the evaluation of children whose performance on irreversible sentences did not present difficulties. A pilot study was developed with 12 autistic children. 3 groups were characterized based on their oral linguistic performance in speech therapy sections, from the less developed (group 1) to the most developed ones (group 3). The results are in line with the literature that distinguishes ALN (language normal) and ALI (language impaired) ASD children. Difficulties in all aspects investigated were identified in children with low production. However, children from all groups revealed difficulties in the syntax-semantic interface and in grammatical number. Children in the intermediate group had greater difficulty in complex sentences and reversible sentences.