Python, Ruby, Haskell - Do they provide true multithreading?

Question

We are planning to write a highly concurrent application in any of the Very-High Level programming languages.

1) Do Python, Ruby, or Haskell support true multithreading?

Answer 1

The current version of Ruby 1.9(YARV- C based version) has native threads but has the problem of GIL. As I know Python also has the problem of GIL.

However both Jython and JRuby(mature Java implementations of both Ruby and Python) provide native multithreading, no green threads and no GIL.

Don't know about Haskell.