Translation:Tá sicín sa cheapaire.
I can't find the skill it is in, but here is a short explanation for you:
- i -> in Used before nouns without a definite article (causes eclipsis): i mBaile Átha Cliath (In Dublin)
- in -> in Used before nouns without a definite article that begin with a vowel: in Albain (in Scotland)
- sa -> in the Used before singular nouns with a definite article (causes lenition if possible): an Spáinn (Spain), sa Spáinn (in Spain)
- san -> in the Used before singular nouns with a definite article that begin with a vowel or vowel sound (so this includes fh): an Ísiltír (the Netherlands), san Ísiltír (in the Netherlands)
- sna -> in the Used before plural nouns with a definite article: na Stáit Aontaithe (the United States), sna Stáit Aointaithe (in the United States)
Because it does. That's just the rule for sa - lenite the following word if it starts with b, c, g, m, or p, and prefix t to feminine nouns that start with s.
It asks to translate "in the sandwich." Why not use san cheapaire since I thought there was an for "the"?
The combination of i and an gives sa.
sa only becomes san before a word that starts with a vowel sound (and because sa causes lenition, and fh is silent, you use san before words that start with f+vowel. For example san fhorais/"in the forest" or san fhoireann/"in the team")