By trying to understand the world around them, children develop their thinking and build their knowledge based on the development of their language; which will one day serve their reading and writing acquisition. However, a child with a primary language disorder, who does not have a sufficiently complex syntax, will very often experience difficulties in reading and writing comprehension, two predictors of academic success. In addition to the development of the representation of the alphabetical system and the structuring of the narrative, the production of a complex syntax is essential for school learning, the following question should be highlighted: what are the learning contexts promoting syntactic extension of children with a primary language disorder? At school, children undergo several different learning everyday contexts where oral expression is used. In this study, interventions with complex discussions were realized in a developmental approach promoting children’s literature with a preschooler who has a primary language disorder. Four contexts were carried out on a daily basis over 12 weeks: interactive reading, gameboard, symbolic play and invented storytelling dictated to an adult. Among a total of 160 videos taken from these interventions, a video of each of these contexts was selected. After the integral transcription of these videos, a selection of 841 spontaneous and natural phrases uttered by the child was taken from the verbatims. The goal was to identify the educational contexts promoting syntactic complexity in children with a primary language disorder. It is through the analysis of the oral syntactic complexity of a child with a primary language disorder across different educational contexts that a comparison of syntactic productions according to the various educational contexts was drawn. The results show that it is during interactive reading that the child has complexified the most of his syntactic structures, which demonstrates that decontextualized narration is one of the best contexts to allow syntactic extension and complexity in children with a primary language disorder. The results of the present study also confirm that the child demonstrates a large zone of proximal development with regard to his syntactic capacities. Teachers are thus invited to offer complex and adapted interventions that will support the child in his language structure. Finally, this research has corroborated a developmental evolution in the complexity of complex sentence structures.