I wrote another comment at https://forum.duolingo.com/comment/6379668 where the speaker says "Conas atá do mhilseán?". I found her 'do' in that one even harder to hear. I came to this one a little further on and could just discern it. Maybe because of all the attention I had paid to the earlier one! But, of course, we all engage in such elision in our normal day-to-day speech. Just a little difficult for beginners.
There is no elision in in either of these exercises - you might not be able to distinguish the individual words, but that's a matter of practice on your part, it's not because the words are being elided.
No. a, o and u are broad vowels. e and i are slender vowels. It has nothing to do with the sound of the vowel, but the sound of a consonent is affected by whether it is adjacent to a broad or slender vowel.
á is a "long vowel" that doesn't sound the same as a, but á is still "broad". é is a "long vowel", but it's still "slender".
I searched my mind for some other words that might help me to know, how it's pronounced, one with the combination "-in" and one with "-an". So "milseáin" is slender, because of the "i". Does it kinda sound like in "cailín" with the tongue pretty close behind your teeth (at the alveolar ridge)? As for "milseán", does that kinda sound like in "nuachtán" with your tongue just a little bit higher (between alveolar ridge and hard palate)?
milseáin isn't slender. The n in milseáin is slender.
I wouldn't compare the sound of cailín to the sound of milseáin, because the í in ín is itself pronounced, whereas the i in áin is primarily there to make the n slender.
I really can't comment on the mechanics of the sound as you describe it.
Jen, you must not try to equate sounds of Irish to sounds of German. As far as I know, German does not have broad and slender consonants. A slender "n" in Irish is really a palatalized "n" with a very slight off-glide, like a [nj] in German, or an "ñ" in Spanish. Other slender consonants do the same thing. If I am wrong, someone please steer me right.
There are a few different classes around, and both UPenn and Villanova University offer undergraduate courses in Irish, but there isn't anything cohesive, and I'm not aware of any open ciorcal comhrá type event, and I don't know that there's the critical mass there for a pop-up Gaeltacht, though the Irish Language Learners facebook group had one last year (May 2017)
Because of the long history of emigration from Donegal to the Philadelphia area, Ulster Irish is often the preferred dialect for Irish learners in Philadelphia.
In American dialects, "sweets" generally refers to sweet things as a group, not as candies per se. A doctor would advise a patient to reduce the amount of sweets in one's diet. I am a senior citizen (77) who has lived in many regions of the USA and have never heard a piece of candy referred to as a sweet except by English speakers in other parts of the world.