A simple question from a Japanese university student: how is that’d pronounced?
My immediate answer was to tell him that it’s ˈðæt əd. I still think that’s the riɡht short answer, but things are actually a little more complicated.
Some relevant variables:
(i) The that element will have a strong vowel, ðæt, only if it is demonstrative, as in that’d be fun, that’d be OK, I don’t think that’d work. If it is a relative pronoun, as in someone that’d been here before, it will almost always be weak, ðət.
(ii) The ’d element may stand not only for would, as in the examples given, but also possibly for had, as in that’d never worked in the past. This makes no difference to the pronunciation.
(iii) There is also the possibility of pronouncing that’d as a monosyllable, ðæd or maybe ðæt, perhaps with further contextual assimilation: that’d be OK ˈðæbbi əʊˈkeɪ.
(iv) for speakers who use t-voicing (esp. AmE), the intervocalic stop/tap in the disyllabic version will be voiced. Here’s a case in point from YouTube.
I can’t find any dictionary entry for that’d that includes pronunciation. Many dictionaries do not even have entries for that’ll and that’s, but leave their pronunciation to be inferred from entries at that and (if you are lucky) ’ll and ’s. LPD does have entries for these contracted forms, though.
The LPD entry at ’d mentions the comparable it’d but not that’d. But now I wonder if I ought to add the possible monosyllabic versions of both.
More generally, in what varieties and styles is it usual to write contracted that’d rather than the usual full that would, that had? I’m really not sure.