Words list validator

I noticed some changes in spelling file from TiagoSantos, that refer to a words list validator. What is it, and what does it do?
Somehow d’r was commented, but it is a valid word in Dutch, and recognized like this by the Dutch tokenizer, which accepts ’ in words, as they should be.

And why is there a comment ‘too short’, will affect other languages. I thought all files were single language?