[ebj73]

I think Image-Line is still using Object Pascal actually, both for the PC and the Mac version of FL Studio. They've been managing the Mac version by using Free Pascal for the compilation. They also have a fair amount of inline assembly, for the performance critical parts, and they have their own in-house GUI and widget library, which, apparently, will compile and run equally well using both Delphi and Free Pascal.

Edit: I notice that the post below says they're using Delphi for both the PC and the Mac version now... It could be a recent development. Last year there were posts on the Image-Line forums saying they were still using Free Pascal, due to the fact that Delphi (at that point) could not produce 64 bit binaries for Mac.

[wila]

Delphi still cannot produce 64 bit binaries for macOS.