The process in which the anatomical structures of the tongue are generated and organized. The tongue is the movable, muscular organ on the floor of the mouth of most vertebrates, in man other mammals is the principal organ of taste, aids in the prehension of food, in swallowing, and in modifying the voice as in speech. [ http://purl.obolibrary.org/obo/UBERON_0001723 GOC:jl ]