Salmoneus wrote: ↑Sat Nov 09, 2019 6:05 amActually, the worst bit is the way that the meaning of certain vowel sequences changes depending on the surrounding context - <oi> can mean any of seven different things, and although the rules are mostly regular, you still have to learn them all. [and in this case, although <oi> can sometimes be <o>, and sometimes <i>, it's actually mostly a way of spelling <e>...]
Yeah, I would say that this is the most problematic digraph. To compound matters, there are cases where <ai> behaves like <oi> due to dialect-specific raising rules.
That's part of the reason Irish orthography is as complex as it is: It's intradialectal, the dialects diverged a long time ago, and there hasn't been much convergence in recent years. The 20th-century spelling reform had to privilege certain variants in order to introduce simplifications and the choice of which was often fairly arbitrary, even when there wasn't a proliferation of forms as with
deartháir and
deirfiúr (simplified from
dearbhráthair and
deirbhshiúr, respectively).
As for diphthongs, Old Irish was rich in them but they had simplified by the Middle Irish period. However, the vocalisation of lenited medial consonants led to the creation of new ones, which explains orthographically complex sequences like <oighi> (Modern Irish
loighic being transparently derived from Latin
logica, for instance). As for the number of apparently doublets, well, some of them represent obsolete contrasts. <mh> historically contrasted with <bh>, but by the early 20th century, the only relic of this was nasalisation in Munster dialects of diphthongs involving <mh>, e.g.
amhras [ˈə̃ũɾˠəsˠ] "doubt" vs.
abhras [ˈəuɾˠəsˠ] "yarn". It was regressive even then and is probably gone today, apart from a few revivalists.
