I'm pretty sure it's a dialectal thing, but aside from an old paper (which mentioned that certain dialects, in the South maybe?, break vowels into those kinda sounds, but that others don't), I've not found anything talking about it.
There really isn't that much at all about the pronunciations of different Gaelic dialects/accents that I've been able to find.
That's really a shame, because a book on that would be really helpful to learners. Most of the speakers in this course have pretty similar pronounciations, so it's not too hard to figure out what they're saying.
One of the speakers, though, is from Eriskay, and her pronounciation is so different from all the others that I have a hard time understanding anything she says. It does seem to be getting easier with time, so maybe by the end of the course I'll be able to understand the Eriskay dialect.