macOS Finding out an Application's Language

In the Finder, Get Info on the app (File: Get Info, or command-I) and there is a part of the window that has the languages that the app includes (localizations). From there, you can deselect languages, add, and even remove languages.
-Chasen

I think Thidranki was referring to the computer language an application is coded in. And the answer is no, there is no way to really tell because all code gets compiled into the same language--assembly. However, certain languages leave behind certain tell-tale signs and by poking around an app's package, you could probably figure out if it was written in Java, C#, Python, AppleScript, etc.

Oh my, do I feel stupid now. Yeah, I suppose that asking what language a program is in the "Mac Programming" section does, if any one person was a reasonable thinker, assume it's the programming language.

jamdr is right about finding what language a program was written in. Sorry I wasn't much help.
-Chasen