ABSTRACT
In the evolution of language there is a difference between phonetics, morphology, and vocabulary. The phonetic system becomes stabilized at a very early age, and remains unchanged thenceforward. The articulatory and grammatical systems are acquired once for all, and owe their stability to the fact that they depend on the identity of the speaker's mind. Family relations also explain the metaphorical use of terms of relationship found in many languages. Social relations, callings, and different technical equipment, all conspire to effect changes in vocabulary, banishing old words or modifying their meaning, and calling for the creation of new ones. The process of generalization, which consists in the application of the name of a particular species to a genus in general, is less frequent, although equally well attested. Changes in meaning throw as much light upon the social conditions of peoples as upon their psychology.
