Student or Learner
I searched the Corpus of Contemporary American English, and was surprised to find there are only 3 sentences with the structure of 'mustn't have done' while there are 167 sentences with that of 'must not have done'. And in the whole of the corpus, there are only 729 'must n't' compared with 3353 'must not'.
Do you American native speakers prefer the form of 'must not' to that of 'mustn't' ? (I was wondering whether it was so.)
Thank you in advance.
What I have noticed in the speech of Americans is how rare it is to hear the use of contractions. Where this is so striking is in the Past Perfect ( and we won't go into the fact that it is also usually something like 'had took'.)
In Britain, it is only when we want to make an emphasis, or assert the truth of a statement that we pronounce the participle; so that when Americans do, I am waiting for some dramatic statement that never comes!
So - I think this avoidance of contractions, as with 'must not', is what you are now noticing.