na's, ti's and de's, pa's and ma's, serve almost as indiscriminately to express a dozen child's ideas as though they had been shaken in a bag and pulled out at random to express the notion that came first, doll or uncle, nurse or grandfather. It is obvious that among words cramped to such scanty choice of articulate sounds, speculations as to derivation must be more than usually unsafe. Looked at from this point of view, children's language may give a valuable lesson to the philologist. He has before him a kind of language, formed, under peculiar conditions, and showing the weak points of his method of philological research, only exaggerated into extraordinary distinctness. In ordinary language, the difficulty of connecting sound with sense lies in great measure in the inability of a small and rigid set of articulations to express an interminable variety of tones and noises. In children's language, a still more scanty set of articulations fails yet more to render these distinctly. The difficulty of finding the derivation of words lies in great measure in the use of more or less similar root-sounds for most heterogeneous purposes. To assume that two words of different meanings, just because they sound somewhat alike, must therefore have a common origin, is even in ordinary language the great source of bad etymology. But in children's language the theory of root-sounds fairly breaks down. Few would venture to assert, for instance, that papa and pap have a common derivation or a common root. All that we can safely say of connexion between them is that they are words related by common acceptance in the nursery language. As such, they are well marked in ancient Rome as in modern England: papas 'nutricius, nutritor,' pappus 'senex;' 'cum cibum et potum buas ac papas dicunt, et matrem mammam, patrem tatam (or papam).'
From children's language, moreover, we have striking proof of the power of consensus of society, in establishing words in settled use without their carrying traces of inherent
- Facciolati, 'Lexicon;' Varro, ap. Nonn., ii. 97.