Will not having learnt a language disadvantage me in a big way?

a knowledge of language is useful if you're dealing with medieval texts. I've never gone so far back as Anglo-Saxon or Old English, but if you have a language background then it can be advantageous if you're examining Middle English texts. I'm only slightly familiar with romance languages, but you can defintely see the influence of those sorts of languages on Chaucer, for example, and it makes reading and deciphering those texts that little bit easier.