Etymologically, More built his word from the Greek οὐ ū ‘not’ plus τόπ(ος) tóp(os) ‘place’ (as in topic, isotope).but then continued
Theoretically it ought to be pronounced with uː— without explaining why.
My thinking was that the Greek vowel ου ū normally maps onto English uː, as in the word acoustic, which is from Greek ἀκουστικός akūstikós (ἀκούω akūō ‘I hear’) and gives English əˈkuːstɪk, not *əˈkjuːstɪk.
I realize now, though, that there are a number of other Greek words with ου ū in which this vowel is indeed mapped onto juː, among them Muse (Greek Μοῦσα Mūsa). In Uranus (Greek Οὐρανός Uranos) the following r diphthongizes the vowel to jʊə or reduced ju; in Luke Λοῦκας and anacoluthon ἀνακόλουθον the yod is dropped because of the preceding liquid.
So it is actually acoustic that is the odd man out. As the OED comments,
The reg. Eng. representative of the Gr. would be acusticin which case I suppose we would pronounce it with a yod. (Actually, in the 1930s the BBC Pronunciation Advisory Council was debating whether to recommend the pron əˈkaʊstɪk, still recorded in the 1963 EPD.)
Likewise, in French it would regularly have been acustique, with y, rather than acoustique with u.
There is another Greek ου word which behaves very strangely in English, namely nous (Greek νοῦς nūs), which we in Britain pronounce naʊs, though the Americans say nuːs.
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I shall now stop posting to the old site: future blog entries will appear only here. You will see above that I have now discovered how to force my choice of font for the phonetic symbols here, just as on the old site.
I will continue to post new entries between 21:00 and midnight each Sunday to Thursday, as before; but since the date is inserted automatically by blogspot they will no longer be postdated to the following day.