The second pronunciation (/-uːst/) is used for the "not accustomed" sense (especially in informal speech), and is a devoicing of the terminal /zd/ to /st/ under the influence of the /t/ of the following to. In very informal situations the final stop is often elided completely, leading to the pronunciation of "unused to" as a single word /ˈʌn.juːs.tə/. In formal speech the second (/-uːst/) pronunciation is frequently proscribed in favour of the fully voiced (/-uːzd/) pronunciation, which is acceptable for either sense and is normally used for the "not used" sense in all registers.
- not used
- I have two unused vouchers for a free meal.
- not accustomed
- I am unused to the dark nights of the countryside.