um...what words? English is not your first language that you have to look up that many?
Ok..I got you now. It is very frustrating isn't it? I think part of the problem is that many spell checkers are not designed to work in multiple languages at one time, let alone in lanuages that are "dead" and unused. So finding one that has a base of words that large is going to be difficult at very best..for all the technology we have..you may end up sitting with a pile of actual books if you are going to use anything that goes that far back.
English is a living thing. Words get added and words get dropped. It's always changing. Have you read the book 1984?