do you want to --> strong form: /du: ju: wɔ:nt tu:/
(stress placement in the utterance depends on what the speaker wants to highlight)
do you want to --> weak form: /ʤjə'wɔ:ntə/
Sounds /d/ and /j/ assimilate into /ʤ/ and /u:/ reduces to /ə/. Then, pronunciation of 'want' doesn't change because this is the main verb in the utterance and must be clear. Finally, /t/ from 'to' is elided and remaining /u:/ sound reduces to /ə/. [There might be different versions of the pronunciation of the word 'want' such as /wʌnt/ or /wɑ:nt/ as well]
Hope it helps,
Seba