To contrast - oh sure there are some obscure C++ language features you can only learn from a mountaintop guru, but there are obscure french features you can only learn in an isolated swiss township.

French is harder - but programming is also hard. One interesting contrast is that programming "languages" might be better placed as wide sweeping paradigms, with learning C++ if you know Java being closer to learning a Boston accent and learning PHP if you know Java maybe learning a new dialect.

Sorry, but this is nonsense.

Fluency in a natural language is a woolly concept. There is no such thing as being "completely fluent." There are various dimensions of language proficiency and even native speakers vary greatly in their abilities. Even the most eloquent writers and speakers of a natural language are ignorant of vast portions of it, after using it for decades.

I'm pretty sure it was a joke...