I found myself confused when my Phonetics teacher corrected the transcription of this sentence from my phonetics exam:
"I don't know how to."
....my transcription was:
.../aɪ 'dəʊn nəʊ ̩'haʊ
tu/
Your version is correct for BrE. Indeed, in this clause-final position, some would even say /tu:/.....
whereas the corrected version was:/aɪ 'dəʊn nəʊ ̩'haʊ
tʊ/.
.....
This is possible, but unlikely, in the clause-final position
I have never seen this tʊ before, and it doesn't appear in the Longman Pronunciation Dictionary by John Wells, for example.
It does appear as a possible weak form in the Cambridge English Pronouncing dictionary, but is not referred to in the notes, which mention only /tə/
So what's your opinion.
Unprintable.