First of all, unlike grammatical errors, explicit feedback such as correction by teachers is not normally given to language learners in the case of the use of the arbitrary linguistic items since any choice among the candidates allowed in a linguistic item is normally correct, as in the adverb positions in English: Already, I have done it., I have already done it., and I have done it already, although each of which might have a slightly difference in meaning.
language learners have little opportunity to adapt the values of the probabilities in their probabilistic module to those in the target language in the first place.