John Walker in his Critical Pronunciation Dictionary (1791) transcribes the pronunciation of the word “gold” as
go¹ld, or go²o²ld
which in modern transcription equates to /goʊld/ or /guːld/.
It is much to be regretted that the second sound of this word is grown much more frequent than the first. It is not easy to guess at the cause of this unmeaning deviation from the general rule, but the effect is to empoverish the sound of the language, and to add to its irregularities. It has not, however, like some other words, irrecoverably lost its true pronunciation. Rhyme still claims its right to the long open o, as in bold, cold, fold, &c.
This made me think of an old post by Janus Bahs Jacquet that describes a late Old English sound change of vowel lengthening before homorganic clusters of voiced consonants, including ld (this is why “wild” and “mild” are currently pronounced with “long i”), and I wondered if this could be the origin of /guːld/: Old English /gold/ being lengthened to /goːld/, which after the Great Vowel Shift would be /guːld/.
However, I found little supporting evidence for this idea. Walker evidently thinks the /uː/ pronunciation was recent in his time (although he could be wrong about this).
But on the other hand, I found a book English as we speak it in Ireland by Patrick Weston Joyce (1910) that says
Such words as old, cold, hold are pronounced by the Irish people ould, cowld, hould (or howlt); gold is sounded goold and ford foord. I once heard an old Wicklow woman say of some very rich people 'why these people could ait goold.' These are all survivals of the old English way of pronouncing such words.
Maybe "survivals of the old English way" here just refers to survivals from Walker's time, not from significantly before. It is interesting however that "ford" also shows this vowel since it also had /o/ before a homorganic voiced consonant cluster in Old English.
The OED says of gold:
Forms: Also ME guold, ME–15 golde, (ME gowlde), 17–18 Sc. and north. dial. gowd.
Etymology: Common Germanic: Old English gold
It doesn’t seem to record any attested Middle English spelling with “oo,” although it’s true that vowel doubling was only inconsistently applied in Middle English to mark vowel length.
I also cannot find any clear examples of other words where Old English short “o” corresponds to modern English /uː/ due to lengthening before homorganic consonants, although I looked through the Bosworth-Toller Anglo-Saxon Dictionary for Old English words containing “ong,” “omb,” “ond,” "ord" or “old”.
The unclear examples that I found were the following:
with -old: mo(u)ld seems similar to gold: it also had “o” in Old English, and the OED says it was spelled with “oo” at some times in the past. But like “gold,” the current standard pronunciation has /oʊ/ rather than /uː/. Bold = “a dwelling” from OE bold is now archaic, but was spelled “boold” at one point in the past. “Fold” = “the earth” (from OE folde) shows no signs of having ever been pronounced with /uː/, but it is not a very common word.
with -ord: ford, mentioned in the Joyce quote above. Board, which has some historical spellings like boord and bourd that hint at /uː/. Hoard, which like board has some spellings like hoord. (The modern pronunciation of these words is an unclear indicator of their original vowel because before /r/, original /uː/ is often conflated with /o/ due to lowering changes, as in whore and floor). Word, which shows a completely different development that may be related to the initial /w/.
with -ong: among comes from Old English on gemange or the phonetic variant on gemonge. The development of the vowel to /ʌ/ seems very unclear to me. It apparently was pronounced with a“short o” sound as the spelling suggests in at least some accents of Early Modern English (John Hart's pronunciation of English (1569-1570), by Otto Jespersen 1907); it seems to me this could either be retained from the “o” variant of Old English, or be derived from the “a” variant via lengthening followed by shortening: /ɑ/ > /ɑː/ > /ɔː/ > /ɒ/. I at one point had the idea that the /ʌ/ pronunciation might come from /o/ > /oː/ > /uː/ > /u/, but there seems to be no evidence for that.
The fact that the letter after the vowel is “l” in particular could be relevant, since vocalization of /l/ to /w/ is a common sound change both historically and currently in English, but I have never heard of a sound change/ol/ > /owl/ > /uːl/ occuring in any other words.
So I find myself stumped, and now I’d like to learn if anyone else knows more about the historical pronunciation of “gold” as “goold” that Walker and Joyce record (and the pronunciation of "ford" as "foord" mentioned by Joyce). Is it as inexplicable and random as Walker makes it out to be, or are there any similar sound changes or historical details that can explain it? Is it related to the fact that "gold" and "old" had different vowels in Old English, as I initially thought, or is this just a coincidence? Do any accents still have it today?