A developmental process, independent of morphogenetic (shape) change, that is required for the hypoglossal nerve to attain its fully functional state. This motor nerve innervates all the intrinsic and all but one of the extrinsic muscles of the tongue. [ http://purl.obolibrary.org/obo/go/references/0000021 GOC:jid http://openisbn.com/search.php?q=0838580343&isbn=1/ GOC:dgh GOC:dph GOC:cls ]