What is the difference between Parallel and Concurrent Programming?
Apart the difference, what languages support which paradigm?
If two concurrent threads are scheduled by the OS to run on one single-core processor, you may get concurrency but not parallelism. Parallelism is possible on multi-core, multi-processor or distributed systems. Concurrent needs to share resources whereas Parallel each process has their own resources at their disposal.
How the code is written differently, that depends on a lot of things.