FOXP2 and language disorder: <i>FOXP2</i>-related speech and language disorders can be classified as "<i>FOXP2</i>-only," wherein intragenic mutations result in haploinsufficiency of the <i>FOXP2</i> gene, or "<i>FOXP2</i>-plus" generated by structural genomic variants (i.e., translocation, microdeletion, etc.)and having more likely developmental and behavioral disturbances adjacent to speech and language impairment.