It's a bit much, but as a follow up, even if these behaviors did not exist during the War for Independence, did language play a role in future Irish resistance? Was it a factor in aggravating The Troubles? Did the IRA use Irish to make a point, or promote the Irish language?
This question was inspired by a post in /r/mapporn.
The simple answer to your first question is yes. The language was an important issue for most Republicans in the 1916-1921 period. The main Irish language advocacy group the Gaelic League was heavily infiltrated by the Irish Republican Brotherhood (IRB). Many republicans had been radicalised while learning Irish. The language was an issue in republican propaganda but I don't remember any campaign that focused solely on it. There would have been a problem with such campaigns as not many people could have understood them. Many speeches used Irish in at least a token way.
In the case of the modern IRA it was probably true that most IRA members support the language but by no means all (or even most) language activists supported the IRA. republican leaders make a point of using Irish in public (a practice they continue today).
Irish was one of the ways nationalists and unionists could be distinguished. Very few Unionists learned Irish.
Sources
Roy Foster, Vivid Faces
Marie Coleman, The Irish Revolution