Ó Séaghdha grew up in Rathfarnham, a suburb of Dublin, in a multi-lingual household.

His father, a linguist, and mother used to speak Irish together but spoke English to their children.

[4][5] Ó Séaghdha describes Irish as "the amazing buried treasure".

[5] In his writing he wants to show people how they, through Irish, can make sense of the world around them, through words and phrases that do not exist in the English language.

[6] The follow-up to Motherfoclóir, published in 2018, which carries the name Craic Baby: Dispatches from a Rising Language, explores the very new and very old parts of the Irish language from a personal perspective, covering the topics multilingualism, Brehon Law, Gaelscoileanna and especially lexicon.