Absolutely! I was just reviewing the comments before I made the exact same comment. Although I'll expand. She does this on a regular basis. I've gotten used to it so I can add the n. I don't know if it's her or if it's a dialect. I'm not sure if there's a grammatical rule or a linguistically one. But she is definitely dropping the pronunciation of the n on the definite article on a regular basis. I don't know if it's only with particular words--like, maybe ones that start with continents--but it's pretty regular.
This speaker is a native speaker from Conamara so I can't speak for that dialect, but in Ulster Irish the "an" can most definitely be shortened to "a" when spoken. Ulster Irish shares some similarities with Gàidhlig where they often don't pronounce the n in "an" and they can even write a' to signify the loss of it. So while "an" is written in Irish, a lot of the time it's lost when speaking, especially when speaking quickly!
It's not just the English translation, it's just the preferred way to say it in English.
Take the sentence Tá úll ar an mbord. You can translate that as either "An apple is on the table" or "There is an apple on the table". Most native English speakers would say "There is an apple on the table". If you add a definite article - Tá an t-úll ar an mbord, you can really only translate it as "The apple is on the table".
So when you have an indefinite article (or no article at all in Irish), you have a choice of which form to use in English, but most of the time "there is ...." is the preferred structure in English. So "Water is at the coast" isn't technically wrong, it just sounds weird, and if you reached that translation by doing a literal, word for word translation of the Irish sentence, I think it should be considered incorrect, because "There is water at the coast" is a much more natural translation.