Palatoglossus develops from:
Occipital myotomes
Lingual swelling of first arch
Third arch
Mesoderm of sixth arch
Muscles of tongue develop from occipital myotomes, so the cranial nerve XII (hypoglossal nerve) supplies all intrinsic and three extrinsic muscles. Only palatoglossus is supplied by cranial root of accessory through pharyngeal plexus and is developed from mesoderm of sixth arch.