FOXP2 and language disorder: Indeed, heterozygous mutations of the FOXP2 gene in humans cause severe speech and language disorders [1], [3], [18]–[20], functional knockdown of FoxP2 in young zebra finches causes incomplete and inaccurate vocal imitation during song learning [11], [20], and heterozygous etiological mutations of the Foxp2 gene in mice impair the acquisition of motor skills [12], [20] without overt effects on innately produced vocalizations of neonate mouse pups [21].