46. The linguals are

The linguals are another non-original series of sounds, coming mainly from the phonetic alteration of the next series, the dentals, but also in part occurring in words that have no traceable Indo-European connection, and are perhaps derived from the aboriginal languages of India. The tendency to lingualization is a positive one in the history of the language: dentals easily pass into linguals under the influence of contiguous or neighboring lingual sounds, but not the contrary; and all the sounds of the class become markedly more frequent in the later literature. The conditions of their ordinary occurrence are briefly these: 1. ṣ comes from s, much more rarely from ç, j, kṣ, in euphonic circumstances stated below (180, 218 ff.); 2. a dental mute following ṣ is assimilated into it, becoming lingual (ṭ, ṭh, ṇ: 197); 3. n is often changed to ṇ after a lingual vowel or semivowel or sibilant in the same word (189 ff.); 4. ḍh, which is of very rare occurrence, comes from assimilation of a dental after ṣ (198 a) or h (222); 5. ṭ and ḍ come occasionally by substitution for some other sound which is not allowed to stand as final (142, 145–7). When originated in these ways, the lingual letters may be regarded as normal; in any other cases of their occurrence, they are either products of abnormal corruption, or signs of the non-Indo-European character of the words in which they appear.

a. In a certain number of passages numerically examined (below, 75), the abnormal occurrences of lingual mutes were less than half of the whole number (74 out of 159), and most of them (43) were of ṇ: all were found more frequent in the later passages. In the Rig-Veda, only 15 words have an abnormal ṭ; only 6, such a ṭh; only 1, such a ḍh; about 20 (including 9 roots, nearly all of which have derivatives) show an abnormal ḍ, besides 9 that have ṇḍ; and 30 (including 1 root) show an ṇ.

b. Taken all together, the linguals are by far the rarest class of mutes (about 1½ per cent. of the alphabet) — hardly half as frequent even as the palatals.