This study delineates the speech and language phenotype of a cohort of individuals with FOXP1-related disorder. Individuals were given standardized tests to examine speech and oral motor function, receptive and expressive language, non-verbal cognition, and adaptive behaviour. Clinical history and cognitive assessments were analysed together with speech and language findings. The interpretation of the results is FOXP1-related disorder is characterized by a complex speech and language phenotype with prominent dysarthria, broader motor planning and programming deficits, and linguistic-based phonological errors. Diagnosis of the speech phenotype associated with FOXP1-related dysfunction will inform early targeted therapy.