Corpus, Concordance & The ETs of Language

Su, do we use 'we perspire during PE lesson' or 'we sweat during PE lesson'?
That was the question that a colleague asked me a few weeks ago. I told her that we would usually use the word perspire instead of sweat. Why she asked? Dictionary said it's fine to use both she continued. I didn't have an answer. It was something that I had been taught. 'Animals sweat while humans will perspire' I told her it was what I remembered my teacher said.

Is that a valid explanation?

Not anymore because I now know better.

Corpus. It was very Greek to me. Is it about some language that is at its death bed? Is English dying and ill....like a corpse that is no longer useful in this digital age? Really amusing. I wonder where the word 'CORPUS' is derived from.

Anyway, it is a set of data of words which has been gathered from the many many conversations of or spoken by people. It has been said that language is fluid, it changes over time etc etc etc. Its like a lightbulb lighting up when I learnt about corpus.

When dictionaries uses corpus to explain certain meaning or usage, I am wondering if I can be confident of its usage. Hmmmm...do humans sweat or perspire? Which is more scientifically correct or does it really matter?