But while there are these many causes, both of individual difference and of differing social environments, why languages do not remain uniform, there are similar causes making for a certain degree of uniformity within a language. There is one very good reason why, to a certain extent, languages do attain uniformity; they are socially acquired. The individual learns to speak a language from those about him, and individuals brought up within the same group will consequently learn to speak, within limits, the same tongue; they will learn to articulate through imitation, and, while no individual ever precisely duplicates the sounds of others, he duplicates them as far as possible. He learns, moreover, as has already been pointed out, to attach given meanings to given words, not for any reason of their peculiar appositeness or individual caprice, but because he learns that others about him habitually attach certain meanings to certain sounds. And since one is stimulated to expression primarily by the desire and necessity of communication of ideas a premium is put upon uniformity. It is of no use to use a language if it conceals one's thoughts. In consequence, within a group individual variations, unless for reasons already discussed they happen to lend themselves to ready assimilation by the group, will be mere slips of the tongue. They will be discarded and forgotten, or, if the individual cannot rid himself of them, will like stammering or stuttering or lisping be set down as imperfections and social handicaps. The uniformity of language within groups whose individual members have much communication with each other is thus to a certain extent guaranteed. A man who is utterly individualistic in his language might just as well have no language at all, unless for the satisfaction of expressing to himself his own emotions.[1] Language is learned from the group among whom one moves, and those sounds and senses of words are, on the whole, retained, which are intelligible to the group. Those sounds and meanings will best be understood which are already in use. No better illustration could be found of how custom and social groups preserve and enforce standards of individual action. [Footnote 1: There have been a few poets, like Emily Dickinson, or mystics like Blake, some of whose work exhibits almost complete unintelligibility to most readers, though doubtless it had a very specific meaning and vividness to the writers concerned.]