"Is toil leam an t-sràid."
Translation:I like the street.
Yes, s always lenites to t-s after the article (an t-sràid the street, an t-sùil the eye, and also eg. ris an t-sagart with the priest because the article in dative also lenites).
Historically it’s basically the same t as in t- before masc. noun starting with a vowel (the d from the old definite article). In Old Irish the eye was int ṡúil (the Old def. article in feminine was something like *indā, it caused lenition of ‘eye’ /suːl’/ to /huːl’/, lost its final vowel and became *ind and then -d devoiced and merged with the h-: /ind-huːl’/ → /intuːl'/ written in OIr. as int ṡúil and in modern Gaelic as an t-sùil).
I write down how I hear some words phonetically in a notebook and using a flash card app (WordHolic) to keep track of the pronunciations. Different people in the course seem to pronounce the words slightly differently depending on the dialect too. If I'm really unsure what I'm hearing I might google the word for a pronounciation also. For example, 'Glic' (clever) - I hear 'gleek' and 'gleesht' pronounced by different tongues. I prefer 'gleek' so I'm gonna roll with it for now!
I’d suggest checking the transcription in Am Faclair Beag – most words are written out phonologically and many additionally have recordings.
As for glic (and many other words with c, t, p after the first vowel) – in most (but not all!) Gaelic dialects there is pre-aspiration of c, t, p after a stressed vowel. And the degree of the aspiration might vary, eg:
(in [brackets] I give full-IPA phonetic transcription, in /slashes/ broader phonological transcription that might be easier to read)
- glic might sound either [kʎiçc] /ɡl´ix´ɡ´/ (as if written glichg) or [kʎiʰc] /ɡl´iʰɡ´/ or [kʎic] /ɡl´iɡ´/,
- mac might sound [maxk] /maxɡ/ (as if machg) or [maʰk] /maʰɡ/ or [mak] /mak/,
- bàta might sound [paːxtə] /baːxdə/ (as if bàchda) or [paːʰtə] /baːʰdə/ or [paːtə] /baːdə/,
- cupa might sound [kʰuxpə] /kuxbə/ (as if cuchba) or [kʰuʰpə] /kuʰbə/ or [kʰupə] /kubə/.
Generally the preaspiration of c is the strongest and of p is the weakest, so most speakers will have /ɡlix´ɡ´/ or /maxɡ/ while fewer will have /kuxbə/ or /kuʰbə/ – but if someone does have /kuxbə/ – they’ll definitely will also say /baːxda/ and /maxɡ/ and /ɡl´ix´ɡ´/.
I think a good general rule-of-thumb to sound OK-ish to general Gaelic ear is to say /maxg/ but /baːhdə/ and /kuhbə/ or /kuʰbə/ (and that’s general the transcription that faclair.com gives).
See Pre-aspiration or What the h in mac is about on Akerbeltz and Scottish Gaelic phonology and orthography: Preaspiration on Wikipedia.