Well, when native speakers use language normally, they don't pronounce every word clearly and distinctly -- they would sound like robots if they did.
Here's what I think is happening:
"who is" -- when native speakers pronounce this in normal speech, they usually put a "w" sound between "who" and "is", to make it easier to pronounce: "whowis". Many speakers also pronounce the first syllable "who" very lightly, so perhaps you just can't hear it very clearly, leaving "wis". Finally, as a non-native speaker, you probably can't hear the difference between "s" and "th" -- a native speaker can hear this difference very clearly.
"who had" -- perhaps this is being pronounced as the contraction "who'd". But it could also be a similar process to the above: the "w" sound is inserted ("whowad"), then the first syllable is dropped, leaving "wad". In normal speech, this is then weakened even further to "wood".
Normally, word which have only a grammatical function are shortened in this way in normal speech; and in English (and some other European languages), we always prefer to pronounce words together, not separately. It's only when we need to emphasise something that we speak very clearly:
"Mr Freud, who IS a psychologist after all..." -- here, we are emphasising the point that Mr Freud really is a psychologist, and so he knows what he is talking about.
This is why learning to speak like a native speaker is so very difficult: you may know all the grammar and all the vocabulary, but there are many, many complicated rules like this which the text books don't teach you.
But don't worry. You understood what the words
should have been, so you do know the grammar. And native speakers will understand you perfectly if you pronounce every word clearly -- you will just sound like a foreigner, but that's OK: you only need to worry about this if you want to be a spy

. Keep listening to English on the news and on the radio, and speak as much as you can with native speakers, and your pronunciation should become more natural.