Sometimes when someone praises me for my writing or I praise myself, my own self-reflection allows me to access the font from which I draw. It is usually reading. As I compose, I am drawing on so much that I’ve read. Just as literary scholars and critics identify the sources of inspiration, style, rhetoric, and lexicon of professional writers, so I identify much less precisely the sources of my own style and choices. But that sense of self-reflection is not immediately observable by outsiders. They have to trust my analysis of my own process.
In the same way, a person who has acquired a language may sense, upon self-reflection, that features of that language have been embedded in his mind in a way so that he may draw on those features for comprehension and expression. It is a feeling, no doubt. And researchers in SLART cannot admit that into consideration because it is not observable and therefore not measurable and therefore not scientific. So Krashen’s acquisition get tossed into the junk mail folder.
Other covert mental activities have been uncovered via very clever psychological experiments. So perhaps some SLART researcher who does not attribute his own proficiency in another language to classroom instruction, study and memorization, practice, and in-country experience but can identify for himself those features that “feel” acquired will develop some way of accessing those internal processes.
Just now I was thinking about how to say to my yard guy that there was no one in Mexico with the money to pay for such yard service (obviously, there are lots of people in Mexico with that kind of money but these guys don’t have access to them). I muttered to myself, “No hay nadie en Mexico que tenga el dinero…..” using the subjunctive after the negative. That is acquired for me, no thought . That’s what I mean when I say internal and invisible.