It is unnecessary here to enter into a prolonged discussion of the other views christened by Max Muller, not without energetic protest from their supporters, the bow-wow and pooh-pooh theories of language. Suffice it to say that the former recognises as a source of language the imitation of the sounds made by animals, the fall of bodies into water or on to solid substances and the like, while the latter, also called the interjectional theory, looks to the natural ejaculations produced by particular forms of effort for the first beginnings of speech. It would be futile to deny that some words in most languages come from imitation, and that others, probably fewer in number, can be traced to ejaculations. But if either of these sources alone or both in combination gave rise to primitive speech, it clearly must have been a simple form of language and very limited in amount. There is no reason to think that it was otherwise. Presumably in its earliest stages language only indicated the most elementary ideas, demands for food or the gratification of other appetites, indications of danger, useful animals and plants. Some of these, such as animals or indications of danger, could often be easily represented by imitative sounds: the need for food and the like could be indicated by gesture and natural cries. Both sources are verae causae; to them Noire, supported by Max Muller, has added another which has sometimes been called the Yo-heave-ho theory. Noire contends that the real crux in the early stages of language is for primitive man to make other primitive men understand what he means. The vocal signs which commend themselves to one may not have occurred to another, and may therefore be unintelligible. It may be admitted that this difficulty exists, but it is not insuperable. The old story of the European in China who, sitting down to a meal and being doubtful what the meat in the dish might be, addressed an interrogative Quack-quack? to the waiter and was promptly answered by Bow-wow, illustrates a simple situation where mutual understanding was easy. But obviously many situations would be more complex than this, and to grapple with them Noire has introduced his theory of communal action. "It was common effort directed to a common object, it was the most primitive (uralteste) labour of our ancestors, from which sprang language and the life of reason." (Noire "Der Ursprung der Sprache", page 331, Mainz, 1877.) As illustrations of such common effort he cites battle cries, the rescue of a ship running on shore (a situation not likely to occur very early in the history of man), and others. Like Max Muller he holds that language is the utterance and the organ of thought for mankind, the one characteristic which separates man from the brute. "In common action the word was first produced; for long it was inseparably connected with action;through long-continued connection it gradually became the firm, intelligible symbol of action, and then in its development indicated also things of the external world in so far as the action affected them and finally the sound began to enter into a connexion with them also." (Op. cit. page 339.) In so far as this theory recognises language as a social institution it is undoubtedly correct. Darwin some years before Noire had pointed to the same social origin of language in the fourth chapter of his work on "The Expression of the Emotions in Man and Animals". "Naturalists have remarked, I believe with truth, that social animals, from habitually using their vocal organs as a means of intercommunication, use them on other occasions much more freely than other animals...The principle, also, of association, which is so widely extended in its power, has likewise played its part. Hence it allows that the voice, from having been employed as a serviceable aid under certain conditions, inducing pleasure, pain, rage, etc., is commonly used whenever the same sensations or emotions are excited, under quite different conditions, or in a lesser degree." ("The Expression of the Emotions", page 84 (Popular Edition, 1904).

Darwin's own views on language which are set forth most fully in "The Descent of Man" (page 131 ff. (Popular Edition, 1906).) are characterised by great modesty and caution. He did not profess to be a philologist and the facts are naturally taken from the best known works of the day (1871).