What does bheatha mean on its own, and how does it form "you are welcome"?
It means "life". The phrase means "it's your life". It's an idiom and is used in the same situations "you're welcome" is in English. Hence why it is taken to mean the same thing.
Thank you! I always appreciate the literal translations of such phrases. I feel it gives a little bit of insight into the culture in which the language developed.
Could somebody point me in the direction of the tip regarding when you use "a" and lenition when addressing someone? I've only just started using the web version, for the very reason that such tips accompany each module.
For me it shows up as the tips for the names lesson at https://www.duolingo.com/skill/gd/Names/tips-and-notes