They had their own "languages" - Turbo Pascal (Delphi) and Borland C++, while not "new" languages, they were both very specific to Borland in their own ways. Their IDE's were much better than just about anything else available at the time. Then they made mistakes and competition came in big time (Visual Studio iirc). Anyway, it was a "long" time ago and I don't remember all of the details, but that's the gist of it.
I'm sure someone will be happy to correct anything I got wrong :)
edit: I don't think this will happen to JetBrains.
edit2: Forgot the "Delphi" name, but it was basically TP w/ libraries.
Your history is a little mixed up there. The original author of Turbo Pascal, and Chief Architect of Delphi, became the Lead Architect of C#. It’s not like Microsoft came out of nowhere and ate Borland’s lunch.
I'm going to guess it's a reference to a language that sells an IDE. Even though Delphi could feasibly be written in any text editor (It was really just Object Pascal) the VCL was the big selling point.
I've yet to write any Kotlin in anything other than Vim and Atom though... and Gradle built those apps just fine. So I'm not sure I see a real comparison here.
I'm sure someone will be happy to correct anything I got wrong :)
edit: I don't think this will happen to JetBrains. edit2: Forgot the "Delphi" name, but it was basically TP w/ libraries.