⁓ interlanguage hypothesis shows that applied linguistic researchers are obsessed with the idea that lang learning is somehow special

this appears to me almost trivially true (but also meaningless); my point is that fucking no one would look at a tennis player learning badminton and from the player taking over habits form one sport to the other would conclude that he must go forth and proclaim that the player is constructing an "intersport" in his mind

see also contrastive hypothesis, another trivially true idea that would amaze no one in a sane field ("did you know that golfers have an easier time learning mini golf than soccer? crazy!")