§ 59. As we have seen, the Irish word corresponding to am, art, is, are, is atá. The negative form, corresponding to am not, art not, is not, are not, is níl (neel).
Examples: níl me mór, I am not big; níl tú óg, You are not young; níl sé, níl sí, he is not, she is not. Níl Art agus Conn ag an tobar, Art and Conn are not at the well. This word níl is a shorter form of ní ḟiul, as we shall se.
§ 60. In sentences like atá Art agus Conn óg, Art and Conn are young, the adjective does not take any special form. In many other languages, the adjective would be in the plural, agreeing with the two subjects of the sentence. So in the sentence atá na fir (fir) óg, the men are young, the adjective óg does not take any new form, although the subject is plural. This is true only of adjectives after the verb "to be".
§ 61. Another use of the preposition ag, at. The English phrases "I am going, I am growing", etc., This was a shorter form of "I am at going". In Irish, ag, at, is always used in translating the present participle; as atá mé ag dul, I am going; atá Conn ag fás, Conn is growing.
In the spoken language, g or ag is always omitted before a consonant; as, a' fás (ă faus). The phrase ag dul (Munster, a dul) is pronounced very exceptionally in the North and West as if ag 'ul (ă-gul). Before words commencing with a slender vowel, the g of ag is pronounced slender, and indeed aig is usually written: as, aig imirt (ĕg-im-irt), playing.
as in English