in taxon results in development of cranial nerve development hypoglossal nerve development cranial nerve 12 development cranial nerve XII development CN XII development The process whose specific outcome is the progression of the hypoglossal nerve over time, from its formation to the mature structure. This motor nerve innervates all the intrinsic and all but one of the extrinsic muscles of the tongue. GO:0021566 anatomical structure development Tetrapoda hypoglossal nerve