Which cranial nerve supplies motor innervation to the tongue muscles?

The hypoglossal nerve (CN XII) provides motor innervation to all intrinsic tongue muscles (longitudinalis superior and inferior, transversus, verticalis) and all extrinsic tongue muscles (genioglossus, hyoglossus, styloglossus) except the palatoglossus (innervated by CN X via the vagus nerve). Damage to CN XII causes ipsilateral tongue deviation toward the side of the lesion (due to unopposed contralateral genioglossus action). CN V provides general sensation to the anterior two-thirds of the tongue (lingual nerve). Chorda tympani (CN VII) carries taste from the anterior two-thirds. CN IX provides taste and sensation to the posterior one-third.