in Irish operates in a similar fashion to Scottish Gaelic. The principal marker is the vocative particle a, which causes lenition of the following initial letter.

In the singular there is no special form, except for first declension nouns. These are masculine nouns that end in a broad (non-palatal) consonant, which is made slender (palatal) to build the singular vocative (as well as the singular genitive and plural nominative). Adjectives are also lenited.