Irish vowels

[Šọ̈́gala]

I can’t figure out whence come the rococo orthographic vowel sequences that are so distinctive of written Irish. For instance, modern Irish “Gaeilge” (“Irish language”), from Early Modern Irish “Gaedhilge”, genitive of “Gaedhealg”. Per Wikipedia, there was some vowel breaking in Old Irish due to metaphony. However, based on my very limited knowledge, it seems that the more dramatic vowel clusters appeared later, in the Middle Irish period. For instance, the example above is from Middle Irish “Gaoidhealg”, from Old Irish “Goídelc”. Are the further developments of cohabiting vowels mostly just orthographic “fictions” that indicate palatalisation or lack thereof for the neighboring vowels? i.e. they were never pronounced as independent vowels. That would explain the “a” in “-dhealg”, but what about the “a” in “Gaoi-“? Maybe some of those vowel pairs are just digraphs that actually indicated a simple vowel? It appears that, in some cases, the sequences of vowels reflected an underlying sequences with glides: e.g. the “taoi-” [tˠiː] in “taoiseach” seems to reflect an underlying *towi-.

[linguoboy]

The use of i and a after e to show the (respectively) slender or broad quality of a following vowel seems to be Modern Irish innovation. At least, this isn't a convention adhered to in my edition of Tochmarc Emire, a text dating to the Middle-Irish period. Are you sure Gaoidhealg is a Middle Irish form? I would've expected Gaedhelg (which is, indeed, one of the variants listed in eDIL).

The history of ao is complicated. In contemporary Scottish-Gaelic and some Ulster Irish dialects, it represents a high back unrounded vowel (i.e. [ɯ(ː)]). In Connacht it merges with /iː/ and in Munster with /eː/. Before slender consonants, it becomes /iː/ even in Munster, e.g. maoin [ˈmʷi̠ːnʲ].

[Šọ̈́gala]

Gaoidhealg is per Wiktionary: https://en.wiktionary.org/wiki/Gaoidhealg ... I don't know how reliable Wiktionary is for this sort of thing.

Any guesses how the first syllable of "Gaedhelg" would have been pronounced? The "ae" would have been a digraph representing either a distinctive simple vowel or diphthong that developed from earlier "oí"? Or heck, maybe it was a simple vowel identical to, say, "e", but with a digraph spelling motivated by etymology.

[linguoboy]

Gaoidhealg is per Wiktionary: https://en.wiktionary.org/wiki/Gaoidhealg ... I don't know how reliable Wiktionary is for this sort of thing.

Generally not bad, but I'm wary of pre-modern forms unless they cite sources. (As I'm sure you know, most English-speakers have only the vaguest grasp of the periodisation of English, and it isn't much better for other languages.)

Any guesses how the first syllable of "Gaedhelg" would have been pronounced? The "ae" would have been a digraph representing either a distinctive simple vowel or diphthong that developed from earlier "oí"? Or heck, maybe it was a simple vowel identical to, say, "e", but with a digraph spelling motivated by etymology.

I'm afraid I'm not familiar enough with the sound system of Middle Irish to say. It had to be sometime in this period that ae and ao monophthongised but I don't know if it was nearer the beginning or nearer the end.