How can I get a modern translation of "The Jew of Malta"?
An interesting question. There are numerous electronic versions of "The Jew of Malta" available. One is provided by eNotes; other sites provide other versions. However, most of the versions I'm familiar with—perhaps all—keep the original vocabulary, or at least part of it. The version at this website is pretty clear: http://www2.prestel.co.uk/rey/jew.htm
I'd use it and the eNotes summary and explanation and between the two you should have a clear modern version.