well, to be honest, i've only had this pleasure a handful of times and when it was done, no, i couldnt tell you what words i'd said.
HOWEVER, i ALWAYS have a strong feeling about what was being spoken to me by the Spirit.
for instance, the first time i fell in the Spirit, it was at a time i was feeling i'd 'failed' God and was in heavy repentance.
i didnt understand what was happening to me or what i was saying while it was going on, but when it was over, i was SO comforted and this thought popped into my head: 'MY LOVE HAS NOT LEFT YOU.'
hope that helps.