I started Monday’s blog with this transcribed phrase:
wʌn ə ðə prɪvəlɪdʒɪz əv biːɪŋ rɪtaəd…
As I was writing it, I hesitated over the word being, before playing safe with the uncontroversial (ˈ) biːɪŋ. The reason is that I tend to relax the first vowel in this word, producing something more like (ˈ)bɪ(ː)ɪŋ. I can do the same with the phonetically comparable seeing, freeing, agreeing etc., and across word boundaries in phrases such as three in a row, three exams. In fact I can optionally do this whenever iː is followed by another vowel. This process (or ‘rule’) is optional and variable, presumably influenced by stylistic factors that I cannot quite pin down.
It’s a special case of the general process I call ‘smoothing’, of which more familiar examples are pronunciations such as faə, paə for ˈfaɪə, ˈpaʊə fire, power. I describe it pretty gnomically in LPD in the note on Compression.
Logically, I think we need to distinguish smoothing (= laxing of a tense high vowel, or loss of the second element of a diphthong) from compression (= reduction of two syllables to one). In any given instance you might theoretically have one or the other or both or neither; but I have always been sceptical about the possibility of compression without smoothing (e.g. monosyllabic faɪə, with a putative phonetic triphthong), although other writers seem to accept triphthongs as a possibility in English with little hesitation.
Thus being ˈbiː.ɪŋ can alternatively be ˈbɪ.ɪŋ (smoothed) or bɪːŋ (smoothed and compressed), but hardly monosyllabic *biːɪŋ, just as fire ˈfaɪ.ə can become ˈfa.ə or faə (or the further derived faː), but in my view can hardly be monosyllabic *faɪə.
There’s an issue how best to transcribe the smoothed form of the underlying long vowel or diphthong: do we write it with length marks (as I did in AofE) or without (as I do in LPD and here)? How do I transcribe smoothed throwing? ˈθrəɪŋ, ˈθrəːɪŋ or ˈθrɜːɪŋ? What do we do if slower ends up sounding identical to slur slɜː, as it may? Where’s my lawn ‘myrrh’?
We normally transcribe RP theory as ˈθɪəri, since it’s an exact rhyme of dreary ˈdrɪəri and weary ˈwɪəri. But I suppose that underlyingly it is (or was) ˈθiːəri, and that in this case the smoothing plus compression has been lexicalized.
This whole discussion applies, I think, only to RP and certain local accents of England, and in particular to varieties such as Norfolk. Probably wisely, when teaching EFL we don’t mention anything beyond at most the fire, power types.