"Must of had" or "Must have had" ? -

                                                                                                                                     ---   That seems to have been the question of my friend Bernie,  so well - let me just pick it up in here.

   

        Right on will I say that between one and the other, the latter is the correct one.   We say: 'I must have fallen asleep.'  Or maybe, 'I must of fallen asleep!'  We say "He must have had it!" and "He must of had it!"But I do hear people interchange these two pairs of utterances, it's true: -  'must have had'  and 'must of had'.   I am not just sure if they also write it as 'must of had' - still, this is not grammatical.... it wouldn't make sense.
       If we were to argue for the grammaticalness or the correctness of  'I must have fallen asleep',  this we have to oversimplify...even if,  by chance, we have to wake up demons of old, uninteresting, grammar classes.   The predicate or the second half of the sentence,  (the first half being made up of the subject 'I'),  is made up of the verb 'fall asleep' preceded by the so-called helping verbs 'must have '.   As it is, we have an instance of  two helping verbs.  The first, 'must', a modal of necessity and the second 'have', the helping verb for a perfected or finished action, when used together puts forward the probable happening of the main verb 'fall asleep'. Which is why,  if I may go on,  rather than thinking of the verb as in the past tense, because it is not time identified, .... it is actually in the past perfect  tense - it is focused on a completed action.

        So that now,  if we were to put together the lexical items, 'must of fallen asleep',  the item 'of' would have no business being there.   For one,  'of'  being a preposition,  it comes before a noun phrase as when we say, 'of Bernie',  'of the sunset',  'of my insatiable curiosity'.   We don't say  'of jumped', or  'of dancing'.   And we wouldn't say, 'of fallen asleep'. Instead, we say 'have fallen asleep.
  
        In the same manner, we could say 'He must have had it!", but sometimes, we hear 'He must of had it!' and the latter utterance is not correct.   We do have an explanation for that, however.   I talked to my granddaughter, Tanya, at the University of Southern California,  and she says:   "I think the proper way is to say 'must have had',  but when you slur it, it kinda sounds like 'must of'.   That's why it's caught on so much we're not sure which one is right."  And I think so, too.,

        I guess,  I'd also want to point out that phonetic concern which makes for the situation.   We actually don't say 'must have had'  in single words all the way.  In speech,  we actually contract it into 'must've had' - what Tanya indicates as 'slur'. And notice that the schwa sound, the 'uh' sound,  in the contracted 've' from 'have' is also the very same sound in  'of' in 'must of'.  Because  'of'  isn't really pronounced with an 'f' sound;  it is, instead, pronounced with a 'v' sound, this is carried over to what Tanya says of  the utterance  'must have' - that it "kinda sounds like 'must of" pronouncing the 'f ' of 'of' here as 'v' and there goes the term 'must of had'   So they do sound the same, but sorry, this does not make our 'must of had' correct.

        Therefore,  if only for the sake of being grammatical,  we use 'must have had' or 'must've had'  rather than 'must of had'!   Right, Bernie?

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      Thanks, Bernie Floresca!
      Thanks, Tanya Parker!