On one of the thread on IGT you gave an IPA transcription that used this symbol ɨ -I can't find the thread, but I would like to know what words in Donegal Irish it appears in because in Korean it as /ɨ/ is an important sound and I can't get the hang of it. If there is a word that has something similar in Irish, I would like to hear it.

Perhaps the sound varies a lot since it is central, but any help appreciated

Ní Lughaidh é is ainm dom, ach tá cuid Cóiréise agam.

Who's teaching you Korean? Korean ㅡ is normally equated with [ɯ] (that is, [u] with the lips spread rather than rounded). In some varieties, it merges with ㅓ [ɤ] (unrounded [o]), but I don't recall meeting any speakers with [ɨ]. In any case, the acoustic difference between [ɨ] and [ɯ] is not large, so I recommend substituting the latter if you can't get the hand of the former.

In Donegal Irish, you'd hear the sound [ɨ] by older speakers for what is spelt "ao", sometimes "aoi". It may be realised as [ɯ] too. Most younger speakers replace them by a long [i].

To my ear it is the sound you both describe and that is what I been using.

Who is teaching me Korean? A native teacher. The problem is that Koreans have 0 ability to analyze their own tongue (I put this down to ultra nationalism and very poor teaching standards here) so if a sound changes by context, they don't seem to understand it is an allophone and tell me I'm wrong, even if I am correct in a given example prior. Also the teacher is female, so will sound a bit different.

The result is that I use [ɯ] and get told I am wrong no matter how I make it. Yet mixing r and l up is quite OK if you are Korean...