"Tá spéis agam sa mhatamaitic."

Translation: I have an interest in mathematics.

[AlmogL]

Is there a difference between spéis and suim?

[scilling]

See this discussion.

[LindaK.Wei]

clicking on the underlined words does not lead to the discussion

[Knocksedan]

They are web links. If you aren't using a web browser, web links may not work.

[JohnWilkinson1]

How would you say "i have an interest in the mathematics" e.g. of nuclear physics?

[Knocksedan]

Tá spéis agam sa mhatamaitic.

The an is already there, it's just not expressed in English unless you are talking about a specific field, as in your example.

[RichardMik2]

Why is this sa and not i?

[Knocksedan]

Because the definite article is used when referring to a topic like this - Chemistry is an cheimic, Latin is an Laidin, etc.

[ZuMako8_Momo]

Why is the s broad and the p slender in "spéis"?

[19O492554]

Words that start with sf, sm and sp are pronounced with a broad s even when they are next to slender vowels - sféarúil, sméar dhubh, spideog. They can be pronounced with a slender s when they aren't at the start - ispíní, cloisfear, etc.

There are a number of exceptions that apply to s, from lenition (sc, sf, sm, sp and st are never lenited) to t-prefixes in certain circumstances, and pronunciation exceptions like this. You could probably do a whole skill on just the letter s!