I wonder how immigrant status works. How much of their bullshit can be explained by non-native language for a test. When you read foreign term for a math notion

I wonder how immigrant status works. How much of their bullshit can be explained by non-native language for a test. When you read foreign term for a math notion (or any term from any domain), often you are unable to identify it, while you are know it and all you need is to read wikipedia article and to recognize familiar math constructions. I might think that the 'proper number' is the 'perfect number', for example. 'Subjunctive scaling' is decidedly is not something I know: it is about logic, I studied it but then successfully forgot after exam. While 'declarative fraction'... What is it? Is it a some way to write down a number in fractional notation and associated set of numbers that can be expressed that way? Probably I know it, just do not recognize the term.