[Mithalwen]

If you have a look at the indexes in the Silmarillion you will get perhaps enough info to give you an idea... but most of the Names in the major works are Sindarin apart from the very earliest characters since the elves that returned to Middle Earth usually became know by the Sindarin versions of their names, Although they were often similar .... ie Feanor not Feanaro and Thingol (not that he was a "returner") not Singollo. Names ending with "we" (and a diaresis over the e that I can not type) are Quenya .