[foldr]

As a linguist, I can assure you that there is no 'linguistic' concept of a context-free grammar as distinct from the mathematical concept.

A language being non-context-free just means that the string language doesn't fall within a certain class. It in fact took quite a while to show conclusively that English was not context-free; it's far from obvious.

None of this has anything to do with 'context' in the sense we're talking about here.