Two of the most under-researched and under-served populations in the field of autism spectrum disorder (ASD), minimally to low-verbal (MLV) individuals and children from low-resource countries, would benefit the most from engaging their parents in research and intervention. First, parents’ unique familiarity with their children could be highly advantageous for language assessment providing a more ecologically valid representation of their children’s abilities. Second, parents’ verbal input, known to predict children’s language, is an important avenue to investigate to guide the development of parent-mediated interventions. Natural language samples, which are used in all three dissertation studies, are ideal for assessing expressive language and for analyzing communicative variations in verbal input. In Study 1, I examined the feasibility of parents (N=33) collecting language samples at home from their MLV children/adolescents with ASD (6;6–19;7years) following a semi-structured elicitation protocol, ELSA-A. I predicted that because of parents’ unique familiarity with their children, they will be better at eliciting speech from them. The results supported this prediction. When with their parents, the MLV children/adolescents produced twice as much speech than when with examiners. Parents collected longer ELSA-As but administered fewer of the recommended activities. Therefore, although parents are not as good at following semi-structured assessment protocols, they elicit speech that is more representative of their children’s everyday abilities. In Studies 2 and 3, I compared the parental input to 37 Bulgarian-speaking (2;7–9;10 years) and 37 English-speaking (1;8–4;9 years) children with ASD matched on expressive language. I compared input in terms of quantity and quality, such as lexical diversity and sentence types (Study-2), and in terms of how parents addressed their children, focusing on personal pronouns, names, and kinship terms (Study-3). Based on past research, I hypothesized that input would differ in quality but not quantity. Indeed, parents’ speech differed in sentence types but not in overall amount. Bulgarian parents asked fewer questions but used more statements. As predicted, they also used significantly more ways to address their children because of the structural characteristics of Bulgarian and potentially different discourse practices. These studies lay the foundation for future cross-linguistic and cross-cultural comparisons in ASD. / 2023-08-30T00:00:00Z