153. An aspirate mute

Deaspiration.

An aspirate mute is changed to a non-aspirate before another non-nasal mute or before a sibilant; it stands unaltered only before a vowel or semivowel or nasal.

a. Such a case can only arise in internal combination, since the processes of external combination presuppose the reduction of the aspirate to a non-aspirate surd (152).

b. Practically, also, the rules as to changes of aspirates concern almost only the sonant aspirates, since the surd, being of later development and rarer occurrence, are hardly ever found in situations that call for their application.