Capitalisation
Capitalisation rules are similar to English. However, a prefix letter remains in lowercase when the base initial is capitalised (an tSín "China"). For text written in all caps, the prefix letter is often kept in lowercase, or small caps (STAIR NA ÉIREANN "THE HISTORY OF IRELAND"). An initial capital is used for:
- The first word of a sentence
- Personal names and placenames, though not the words an, na, de (Micheál Ó Murchú "Michael Murphy"; Máire Mhac an tSaoi "Mary McEntee" de Búrca "Burke"; Sliabh na mBan "Slievenamon")
- Adjectives from personal names and placenames; though not for adjectives used in extended senses (bia Iodálach "Italian food", but cló iodálach "italic type")
- Names of months, feast-days, and languages (Meán Fómhair "September"; Oíche Nollag "Christmas Eve"; Fraincis "French")
- Names of days of the week (an Luan "Monday"), as well as Dé (Dé Luain "on Monday")
- Definite titles
- Names of God; though not pronouns referring to God
Read more about this topic: Irish Orthography