As for When Vowels Get Together V2.1, discussed here, I'm releasing an excerpt from the new release (coming Real Soon Now). It is the notes from the IO chapter, which occasionally suffer from a lack of context but are generally quite readable (I'd say).
The Macmillan English Dictionary transcribes this with the sound /iə/, but the audio sample has a clear /iəʊ/. The variation is largely dependent on register.
- bullion and medallion
These two words are alone, according to Macmillan English Dictionary, among all other '-llion' words (billion, million, mullion, pillion, stallion... etc. – which have the sound /jə/). Either sound is acceptable for any of these words.
The Macmillan English Dictionary has no transcription of this word. It is listed here among /iə/ words following the audio sample. Many speakers, however, would pronounce it with the sound /iɒ/.
- reunion versus unionThe Macmillan English Dictionary transcribes the first of these as /iə/ and the second as /jə/. This is not a systematic or meaning-bearing distinction. A student may use either with perfect clarity.
The Macmillan English Dictionary transcribes this with the sound /jə/, but the audio sample has a clear /iə/. Either is acceptable.
- Million, mullion, and scallion etc. See note 2 with regard to the Macmillan English Dictionary's distinctive treatment of bullion and scallion.
- audioconferencing, labiodental, physiotherapy, radioactive etc.
Each of these is the sole representative of words that can be formed with its prefix. The Macmillan English Dictionary transcribes idiosyncrasy with the sound /iəʊ/, but the audio sample has a clear /iə/. The variation is largely dependent on register. (The transcription of idiosyncratic matches the audio sample – /iəʊ/.)
The Macmillan English Dictionary transcribes this with the sound /iəʊ/, but the audio sample has a clear /iə/. The reader presumably misread it, assuming that it was a sort of window. This would not be surprising; both words are fairly rare. But while the British National Corpus notes 69 instances of oriel (the window, pronounced with the sound /iə/), it has a mere five instances of oriole, and two of them point to the same text. One of the remaining four refers to '1926'. The word, like the bird, is nearing extinction – in the UK, at least. (Understandably the balance is reversed in Corpus of Contemporary American, a corpus well over four times as extensive as BNC, as America has both different architecture and a different bird population: oriel – 20, oriole 187.)
Other '-atio' words (fellatio and ratio) have the diphthong /eɪ/ in the stressed syllable, followed by /ʃ/. In patio it is /æ/ in the stressed syllable, followed by /t/.
The Macmillan English Dictionary transcribes this with the sound /iəʊ/, but the audio sample has a clear /iə/. The variation is largely dependent on register.
The Macmillan English Dictionary transcribes the first syllable as /ɪ/, but the audio sample has a clear /i:/. With recently-borrowed foreign words there is much variation. The second syllable varies from /k/, through /ʧ/ to /ʃ/ (reflecting the English radish), followed by choices of /i/ and /ɪ/, /ɒ/ and /əʊ/ – even, very occasionally [o].
The Macmillan English Dictionary transcribes this with the sound /ʤəʊ/, but the audio sample has some kind of vocalic glide between the /ʤ/ and the /əʊ/.
- Number of members
There is another similar sound (/aɪɔ:/) that is in the Other Sounds section, as there is only one representative of it and the three family members that are included often cluster around related words, such as biochemical/biology/biological in which the /aɪ/ is followed by /əʊ/, /ɒ/, and /ə/ respectively.
The Macmillan English Dictionary transcribes this with the sound /aɪɒ/, but the audio sample has a clear /aɪə/. This is probably a mistake, possibly by mistaken analogy with ioni[s/z]e (though the relative rarity of the verb might throw this explanation into question).
The Macmillan English Dictionary does not list this word; the link is to the Collins English Dictionary.
The Macmillan English Dictionary transcribes this with the sound /aɪɒ/, but the audio sample has a clear /iə/.
The Macmillan English Dictionary transcribes this with the sound /aɪʊ/, but the audio sample has a clear /aɪɒ/, possibly by analogy with biography . With newly-constructed portmanteau words like this, supposed etymologies are common. In this case, the possible 'donors' are bio-, biography or biographical – biography won out in this case because of the stress /baɪ'ɒpɪk/ as opposed to the transcription – which is stressed on the first syllable).
- brioche and kiosk
These two, alone amongst the Macmillan English Dictionary's transcriptions of /iɒ/, has a long /i:/ (as the stress is on the /i:/). The Macmillan English Dictionary's American examples of brioche have stress that is more sympathetic to the French original, and the shorter vowel (in the first syllable) that goes with the lack of stress.
Mammon (When Vowels Get Together V4.0: Collection of Kindle word-lists grouping different pronunciations of vowel-pairs – AA-AU, EA-EU, and IA-IU, and – new for V4.0 – OA-OU. 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 32,400 views**, and 4,400 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 1570 views/700 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.