Here is the latest tranche (not as trencher-like as previous instalments; less to get your teeth into) because the vowel pair in question isn't so prolific.
Vowel sounds represented by the spelling 'UO'A large proportion of words spelt with the vowel pair '-uo-' (57½%, to give a percentage that on such a small sample size is not particularly significant) are excluded along with other words spelt with the ending '-ous' (as explained here [the link doesn't work here]), specifically '-uous' . The Macmillan English Dictionary provides two transcriptions of these 35, assigned apparently randomly: /juə/ and /jʊə/.
This apparent discrepancy suggests the hypothesis that the prefix in some way 'causes' a supposed vowel change.The words discontinuous and inconspicuous have /u/, and continuous and conspicuous have /U/, which supports this hypothesis. However both ingenuous and disingenuous have /ʊ/, which suggests that the beginnings of a seeming pattern are illusory.
Another possibility is that a stressed vowel in the preceding syllable goes with /ʊ/. This rationale works for both continuous and conspicuous, but not for ingenuous, which has /u/. Perhaps the apparent distinction is just accidental(1).
- Words spelt '-uous'
The apparent randomness might be explained in this way: at first two researchers were working on these words (words spelt with an initial a-f were shared equally between /juə/ (2 a-s. 3 d-s, 1 f-) and /jʊə/ (1 a-, 4 c-s, 1 e-) . One oddity resulting from this division of work was that discontinuous is transcribed one way and continuous another. For the 17 words with initials from i-to- the researcher with a preference for /juə/ was working alone. For the last 6 words, tu-v the researcher /jʊə/ was working alone.
But my use of was and were in this tale of backroom staff management is entirely speculative; the distinctive transcriptions may have fallen either way completely by chance. In any case, the student may safely ignore the distinction.
Macmillan English Dictionary uses the transcription /flɔ:'resənt/, but the audio sample has a similar diphthong to the one in the word transcribed as /'flʊərəʊkɑ:bən/. Meanwhile, as further evidence of the variable pronunciation of this vowel sound, the words fluoride and fluorine are transcribed with the diphthong /ʊə/ but have an audio sample with a monophthong that is not unlike /ɔ:/.
The Macmillan English Dictionary gives the transcription /dju:əʊ'di:nəm/, but the audio sample gives both unstressed vowels as /ə/. Again,
Mammon (When Vowels Get Together V4.1: Collection of Kindle word-lists grouping different pronunciations of vowel-pairs – AA-AU, EA-EU, IA-IU, OA-OU, and – new for V4.1 – UA-UE. If you buy it, contact @WVGTbook on Twitter and I'll alert you to free downloads of the forthcoming volumes; or click the Following button at the foot of this page.)
And if you have no objection to such promiscuity, Like this.
Freebies (Teaching resources: nearly 33,500 views** and 4,600 downloads to date. They're very eclectic - mostly EFL and MFL, but one of the most popular is from KS4 History, dating from my PGCE, with 1637 views/740 downloads to date. So it's worth having a browse.)
** This figure includes the count of views for a single resource held in an account that I accidentally created many years ago.