"any language, such as VB, Delphi, C,"

They're all programming languages - which one you choose is largely a matter of personal experience & preference.

To simulate an 8051, you're going to have to deal with its bit-handling; AFAIK, none of the above has this as a standard feature. However, some Pascal variant implement Sets as bitmaps - which can give you very neat HLL bit handling. And you can use a Variant Record to access an object as bits or bytes. Dunno if this applies to Delphi, though?