Reduced particles

Johnny   Wed May 07, 2008 4:14 pm GMT
There are a lot of particles (usually short adverbs, etc.) that are reduced in speech when they are NOT STRESSED, especially in fast speech. Are the following reductions common? I have trouble hearing them, because they always seem either non-reduced or half reduced to me. Thanks.

when -> wən / wɪn
where -> wɚ
there, their, they're -> ðɚ
have -> həv (Have you seen it?)