The problem how language has developed was first answered by the onomatopoetic theory, “the bow-wow theory” as Max Müller calls it. Language was conceived as an echo of nature, as a reflex action that takes place in a living and feeling being. Yet this theory had to be abandoned, because an historical investigation of language proved that words with very few exceptions were not imitations of external sounds. Yet the spirit of investigation was not daunted by this defeat, and the bow-wow theory reappeared in a modified form. Language was still considered as a reflex action; however, it was conceived to be a reflex which re-echoed the impressions of natural phenomena as they had affected man. This was the exclamation theory which seeks the origin of language in the “ohs and ahs,” the sighs and shouts of a feeling mind. Prof. Max Müller calls this theory “the pooh-pooh theory.” This theory had also to be discarded because it was in conflict with the actual facts of the evolution of language. Next Noiré and Prof. Max Müller came with their theory, called by Noiré “the synergastic theory,” which conceives language as the expression of common work, also called by Noiré the Logos theory, the sympathetic theory, and the causality theory. Prof. Max Müller in order to forestall any deriders of this theory suggests calling it “the yo-he-ho theory,” yo-he-ho being the sailors’ song when engaged in some common work as hoisting or hauling. This yo-he-ho theory actually explains the origin of language, and it is, so far as we can see, not in conflict with any historical or philological facts. But in honor of the inventors of the onomatopoetic theory it must be recognised that the main idea of the yo-he-ho theory is the same as that of the bow-wow theory. The main idea is this: Language did not originate in man’s mind out of itself in some mysterious way representing a break in the continuity of evolution, but it is a certain reflex-action of living and feeling beings taking place in consequence of external stimuli. This reflex-action however is not direct, but indirect. It is not that of a single being, it is the reflex-action of a whole society, engaged in common work. It developed in consequence of their common activity and through their want of intercommunication. * * * * *