[…] a series of hypotheses that make up a coherent theory of...

[…] a series of hypotheses that make up a coherent theory of second language acquisition. According to the rules of scientific method, it will always be "just theory" and never be "definitely proven". The hypotheses I will present have, however, been found to be consistent with a significant amount of data, experimental and otherwise, and have not yet been confronted with serious counterexamples, in my view. They make up, collectively, my "position". This does not mean that I necessarily "believe" them. What it does mean is that these hypotheses are consistent enough with existing data to be worthy of consideration, and that they appear to capture the data better than other existing generalizations.
KRASHEN, Stephen. Principles and practice in second language acquisition. (1982, p. 02)
O linguista estadunidense Stephen Krashen é conhecido mundialmente por sua teoria de Second language aquisition. Em seu trabalho, ele elaborou uma teoria geral sustentada por cinco hipóteses que visam analisar e explicar como um falante adquire uma segunda língua. Dentre as alternativas abaixo, qual não é uma hipótese proposta por Krashen?