_Genitive._ The genitive plural of monosyllables and masculine polysyllables is twofold, like the nominative singular, and like the nominative plural; as, righ m. _a king_, g. p. righ or righre. The genitive plural of feminine polysyllables is like the nominative plural only; as, amhainn f. _a river_, g. p. aimhnichean. Suil f. _the eye_, has its g. p. sùl.
_Dative._ The dative plural is formed from the nominative plural by changing the final vowel into _ibh_; as, coluinn f. _the body_, n. p. coluinne, d. p. coluinnibh; cridhe m. _the heart_, n. p. cridheacha, d. p. cridheachaibh.
_Vocative._ The vocative plural is like the nominative plural; as, duine m. _a man_, n. p. daoine, v. p. dhaoine.
Final _a_ or _e_ in all the singular cases of polysyllables is occasionally cut off, especially in verse; as, leab _bed_, teang _tongue_, coill _wood_, cridh _heart_.
In nouns beginning with a consonant, all the cases admit of the _aspirated form_. In the vocative singular and plural the aspirated form alone is used, except in nouns beginning with a lingual, which are generally in the primary form, when preceded by a lingual; as, a sheann duine _old man_. Nouns beginning with _s_ followed by a mute consonant have no aspirated form, because _s_ in that situation does not admit of the aspirate. In nouns beginning with _l_, _n_, _r_, a distinction is uniformly observed in pronouncing the initial consonant, corresponding precisely to the distinction of primary and { 55} aspirated forms in nouns beginning with other consonants. This distinction has already been fully stated in treating of pronunciation.
The general use of the singular and plural numbers has been already mentioned. A remarkable exception occurs in the Gaelic. When the numerals fichead _twenty_, ceud _a hundred_, mile _a thousand_, are prefixed to a noun, the noun is not put in the plural, but in the singular number, and admits no variation of case. The termination of a noun preceded by da _two_, is the same with that of the dative singular, except when the noun is governed in the genitive case, and then it is put in the genitive plural[38]; when preceded by fichead, ceud, &c., the termination is that of the nominative singular; thus da laimh _two hands_, da chluais _two ears_, dà fhear _two men_, fichead làmh _twenty hands_, ceud fear _a hundred men_, mìle caora _a thousand sheep_, deich mìle bliadhna _ten thousand years_[39].