Try not to think about this one too hard - it might make you sweat. That word we use to describe the process of sweat forming in our pores and escaping onto the skin is another one of those where your eyes and your brain conspire against you at the beginning. It's the opposite of the problem we had with "prescription" earlier on in the list.
If you hear someone say "pre-spire", then don't correct them straight away, that might stress them out, and stress is one of the major causes of perspiration! Instead, find a quiet moment later on and gently tell them that the right way to say it is "per-spire". It's yet another one that's spelled as it's supposed to be said. We're still not totally sure how we managed to mess up so many words.