Need advice on Modern Germanic

But other non-language boxes like boxes for coding languages, scripts,... are exactly that : one's knowledge in a field. Nobody can ever be a gem-pro-4 like someone can be a sp-4. But someone can be a gem-pro-4 like someone is lua-4. At least that's how I think about it.

Ideally, our PHD would know not only soundlaw algebras and conjugations, but also have an excellent grasp of Gothic, Old Norse, ...; which would afford him a solid (Proto-)Germanic vocabulary.

Anyone can have an excellent grasp of Gothic and Old Norse if they studied it. So, yeah, probably, but it depends on what he remembers.