hmm that's an interesting question. i've never thought about it to be honest; the placement of a word like sukoshi seems natural to me...
David, i know what you're saying, but in this case it's not true.
'watashi wa nihongo ga sukoshi wakarimasu'
'demo sukoshi nihongo ga hanasemasu'
to put the sukoshi anywhere else in either of the above sentences would sound incorrect. well, it would still be understandable, but would not sound natural.
hmm, i'll think about it, but without a grammar book i can't give a concrete answer sorry.