Downing Street has said the government, with the exception of Mr Hunt who has a quasi-judicial role in the final decision, will back the motion. The prime minister's spokesman said the motion essentially reflected what Mr Cameron had said on Monday.He pronounced the prefix quasi- as ˈkwɑːzaɪ.
This pronunciation, while by no means unusual, is interesting in that it combines in the same morpheme two different ways of treating Latin words taken into English.
One is to follow the usual English reading rules (spelling-to-sound rules), which treat long vowels as having undergone the Great Vowel Shift. This is what is done for Latin words that are well integrated into English. Thus we have for example creator and major with -eɪ-, and aquarium with -eə- deriving from an earlier -eɪ-. Likewise, we have for example appendicitis and minor with -aɪ-.
The other is to give the long vowels ‘continental’ values, rendering Latin ā as ɑː and ī as iː. This is what we do with words perceived as being less thoroughly integrated. We usually pronounce errata with -ɑː- nowadays, though that was not always the case. Similarly, in vivo usually has -iː-. (But viva meaning ‘oral exam’ is ˈvaɪvə.)
The word quasi ‘as if, as it were’ actually has short vowels in Latin, quăsĭ. Latin stressed short ă is normally mapped onto English æ, eg aquifer, per capita, so this prefix ought to be ˈkwæsi. But English speakers are often pretty cavalier with Latin vowel quantities in English, and even those who have studied Latin (such as Mr Cameron, who must have done it at Eton) often get them wrong. If, as is usual, the vowels in this prefix are treated as long, we should get either GV-shifted ˈkweɪzaɪ or ‘continental’ ˈkwɑːsi(ː). Dave’s ˈkwɑːzaɪ is a combination of the two.
Given the further uncertainty over whether or not to voice the intervocalic s — is it s or z? — we end up with quite a combinatorial explosion of possibilities for this humble prefix.