Individuals carrying heterozygous mutations of FOXP2 display a complex speech and language disorder phenotype involving impaired articulation caused by an inability to coordinate the complex sequences of orofacial muscle movements required during speech (developmental orofacial dyspraxia; OMIM 602081), accompanied by both expressive and receptive linguistic and grammatical processing defects (Vargha-Khadem et al., 1995, 1998; Watkins et al., 2002a). Here, FOXP2 is linked to language disorder.