§ 7. Origin of Conventional Language. — The language of natural signs is pervaded by the systematic unity of a single formative principle — that of imitation. This gives it so strong and tenacious a hold upon the mind that it can only be displaced by a conventional language which has also a systematic unity of plan. It can never be displaced by a chaotic multiplicity of detached and disconnected signs, each of which has to be separately remembered by an independent mental effort. The human mind could not endure so burdensome a load. The conventional signs which are to displace imitative gestures must therefore form some kind of system, unified by general formative principles. Now visible gestures are theoretically and practically capable of forming a conventional system. The deafmute is sometimes taught a fingerlanguage which is purely conventional. He makes a limited number of easily remembered manual signs, each corresponding to a letter of the alphabet, and by successively combining these he spells out words and sentences. Such a language has a unity of composition which makes it manageable. There is in it a systematic correspondence between expression and meaning. Where meaning is partially similar, expression is partially similar; where meaning is modified, expression is modified in a corresponding manner and degree. But the important point is that the systematic unity of composition belongs in the first instance to articulate speech. The manual alphabet is merely a translation of the oral alphabet. Further, it could only have been devised after articulate utterance had been already analysed into its elementary constituents. Now a conventional system of manual or other visible movements analogous to the conventional fingeralphabet could not grow up spontaneously out of a previous system of imitative gestures. We might as well expect a deafmute or an untutored savage to invent the steamengine or the electric light. A limited and easily manageable set of manual signs is required. But on what principle are the signs to be selected, and on what principle are they to be limited? Oral language had been in use for long ages before its alphabet was discovered. But the invention of a similar system of visible signs would have been incomparably harder than the discovery of the alphabet. The discovery of the alphabet was the discovery of unity of composition in a structure already existing and familiar to mankind. But the independent invention of a visible alphabet would have been not a discovery arising through reflective scrutiny of familiar experience, but a highly artificial creation.

On the other hand, articulate utterance is as a natural process characterised by unity of composition. This unity of composition is determined by the structure of the organs of speech. There is no need to invent an alphabet before combining elementary sounds in syllables and words. The alphabetical sounds which form the vital constituents of all speech were, as Ferrier says, "there from the beginning." Undetected, but yet present and operative, they made possible a systematic correspondence between meaning and expression. This correspondence is not indeed of the same kind as that which characterises the imitative gesture. Any isolated imitative gesture has a direct affinity with the thing it represents. The absence of this direct selfinterpreting affinity is just what distinguishes the conventional from the natural sign. None the less, systematic correspondence is possible where there is no direct resemblance. The rise and fall of the mercury in the thermometer corresponds to the rise and fall of temperature, but it does not resemble it. So, apart from all similarity between sounds and what they signify, there may be a correspondence between the relations of sounds and relations of meaning. Where meaning is partially similar, its utterance may be partially similar; where meaning varies more or less in this or that special manner, expression may vary more or less in a corresponding manner. This we find to be the case in all known languages.

It is here that philological analysis becomes important. In all languages there are traceable certain comparatively elementary phonetic components called roots, expressing primary universals or products of conceptual analysis; and these roots variously modified and entering into various combinations express conceptual synthesis or discursive thinking. They blend and combine in continuous speech just as the corresponding concepts blend and combine in continuous thought. This is possible because of the ultimate unity of composition of the phonetic material, which is resolvable into elementary alphabetic sounds which do not occur in isolation but as parts of an articulate complex.