In reply to Reuben:
In reply to dave_59:
I also heard some engineers say if your testcase is used in silicon. What is this?
That is what I meant by used in manufacturing - when your test is applied to a supposedly working piece of silicon. That is a test to make sure the manufactured part matches the specification used to build it.
The rest of your question is a very broad topic. You can use many different languages to create stimulus to a DUT. It really depends on what the application is and the resources available to write the code.
Software testing generally refers to testing software that is part of a product deliverable, not software used to test hardware.