Our research on typically developing children was used as a benchmark for studies of children with language impairments. Professor Rosalind Thornton extended the biolinguistic approach to language impairment in children (e.g., Thornton, Rombough, Martin, & Orton, 2016). This work was conducted in collaboration with two speech pathologists as co-authors (Martin & Orton) and published in a special issue of First Language, dedicated to Professor Heather van der Lely. The experimental findings supported the view that children with specific language impairment (SLI) have the same innate capacity to acquire language as typically developing children, but their language growth is considerably slower (i.e., delayed but not fundamentally different). Understanding the delays in using plurals in typically developing children led to a study demonstrating a delay in the comprehension and production of syllabic plurals by 5-year-old children with SLI (Tomas, Demuth, & Petocz, 2017).