Middle English

This is the only reading of Pearl in the original Middle English that I can find. It is not too accurate and is only the first part of the poem, but it will at least give you some idea of what the poem might sound like in its original form and will help you with your reading:

https://www.youtube.com/watch?v=xU497BZRyHs

This is a very good reading of another poem by the  Pearl Poet, Sir Gawain and the Green Knight:

https://www.youtube.com/watch?v=GrnXgVTTrCI

There is indeed a Middle English dictionary:

https://quod.lib.umich.edu/m/med/med_ent_search.html

And here is an introduction the language. Fortunately it is an old form of Modern english and not near as different as Anglo-Saxon!

http://www.nativlang.com/middle-english/index.php