Studying What?

I normally tell people I'm learning "Irish", which most of my friends understand to mean that non-English language some people speak in Ireland. I'll specify 'Irish Gaelic' if I need more detail.

But what is this language really called? English speakers use 'Irish', 'Irish Gaelic', or sometimes just 'Gaelic'. The latter, though, is often understood to mean Scottish Gaelic and not the Irish sort. There are a suprising number of people who think that 'gaelic' is a single language spoken by Scots and Irish and that it is "mostly dead".

They are related langauges. of course; Irish is a Celtic language, and belongs to the goidelic language branch along with Scots Gaelic (gaedhlig) and Manx (gaelg). Ethnologue also notes a fourth, extinct language: Hiberno-Gaelic.The other branch of the Celtic languages, brythonic, includes Welsh, Breton, and Cornish.

The official name of the language in Ireland is Gaeilge (pronounced variously as ge:lik or ge:l'g'ə). Before the spelling reform in the 40s, it was Gaedhilge. There are some regional spellings and pronunciations, as well: gaedhlag is Ulster, gaedhealaing, gaouluinn or gaelainn in Munster. They all refer to the same thing, but it does explain why the Munster Irish lessons (Rosetta and Pimsleur) seem to be saying 'guael-lun'. I have read that this is considered an archaic form, which is in keeping with many of the Munster Irish forms. The common form of gaeilge reflects the Connacht pronunciation. Ulster is the outlier, I guess. guael-lig or guael-lik, much more like an English speaker would attempt to say 'gaelic'.

Wikipedia notes that the archaic term erse (a word that is probably not familiar to anyone except crossword puzzle fanatics) is no longer used and may be considered derogatory.