23. Seven[1] of the consonants can be eclipsed, viz. b, c, d, f, g, p, t; the others cannot. Each consonant has its own eclipsing letter, and it can be eclipsed by no other. The eclipsing letter is written immediately before the eclipsed letter, and is sometimes, though not usually in recent times, separated from it by a hyphen, as m‑bárd or mbárd (pronounced maurdh).
Formerly eclipsis was sometimes shown by doubling the eclipsed letter: thus, a ttarḃ, their bull. Whenever a letter is eclipsed both should be retained in writing, although only one of them (the eclipsing one) is sounded.
24. It is much better not to consider the letter s as an eclipsable letter at all. t replaces it in certain positions, but in none of those positions (dative singular excepted) in which the other letters are eclipsed. In fact, s is often replaced by t when the previous word ends in n, as an tsúil, the eye; aon tsál, one heel; sean t‑Síle, old Sheelah; buiḋean tsluaġ, a crowd, &c. Some, however, maintain that s is really eclipsed in these cases, because its sound is suppressed, and that of another consonant substituted; but as the substitution of t follows the rules for aspiration rather than those for eclipsis, we prefer to class s with the non-eclipsable letters, l, m, n, r, s.
- ↑ Eight is the number given in other grammars. They include the letter s.
