I switch between Ruby and C++ frequently. My trick, which I admit is complete unplanned fluke, is different IDEs. Sublime for Ruby and XCode for C++. They look so different that my brain just disregards the other language. I briefly tried Ruby in XCode and nothing made any sense.
Assuming you don't want to install multiple editors, perhaps different colour schemes might produce something similar in your brain.
I feel like the words "3dfx Voodoo Banshee" just unlocked a part of my brain, full of IRQ conflicts and blue screens, that I had been keeping firmly closed.
I think the people I'd put in "Group D" would be the ones that respond immediately and expect an ongoing conversation. I can't imagine reaching out once a year to confirm we're both still alive!
Delphi was my first introduction to programming with Borland Delphi 3 on a magazine coverdisc before we had the internet. At 12 years old and just getting into computers, I considered .exe applications with their lovely grey components to be so professional and unattainable that the ability to build my own was mind-blowing. A few years later, I had some of my freeware that I'd built in Delphi featured on that same magazine's coverdisc!
I eventually went down the web development route but I've recently, via Arduino, learnt C/C++, and am enjoying desktop development again. Compiling is exciting!