What do philosophers mean when they say language has a psychological reality?

Question

I came across this in trying to understand 'Ignorance of Language' by Michael Devitt, and the back and forth he has had around this topic with other philosophers. Any books (papers?) I can look at to understand a bit more about those who agree with the psychological reality of language and those who do not? The blurb from Devitt's book, for context:

"The Chomskian revolution in linguistics gave rise to a new orthodoxy about mind and language. Michael Devitt throws down a provocative challenge to that orthodoxy. What is linguistics about? What role should linguistic intuitions play in constructing grammars? What is innate about language? Is there a 'language faculty'?

These questions are crucial to our developing understanding of ourselves; Michael Devitt offers refreshingly original answers. He argues that linguistics is about linguistic reality and is not part of psychology; that linguistic rules are not represented in the mind; that speakers are largely ignorant of their language; that speakers' intuitions do not reflect information supplied by the language faculty and are not the main evidence for grammars; that the rules of 'Universal Grammar' are largely, if not entirely, innate structure rules of thought; indeed, that there is little or nothing to the language faculty.

Devitt's controversial theses will prove highly stimulating to anyone working on language and the mind."

Answer 1

Devitt summarizes and defends his claims here.

He makes the following distinctions:

1. Distinguish the theory of a [linguistic] competence from the theory of its outputs/products or inputs.
2. Distinguish the structure rules governing the outputs of a [linguistic] competence from the processing rules governing the exercise of the competence.
3. Distinguish the respecting of structure rules by processing rules from the inclusion of structure rules among processing rules.

And then he describes what he means by the "linguistic conception" versus the "psychological conception":

I take the linguistic conception of grammars to be the view that a grammar is a theory of the nature of the system that constitutes a language, and the psychological conception to be the view that a grammar is a theory of the psychological reality of a language in its competent speakers

From this he concludes that the psychological conception is wrong, and the linguistic conception is right.

To summarize even more, he's saying that the rules developed in linguistics are structure rules (having to do with relations between strings of words), not processing rules (having to do with calculations done by the brain).

Or in other words, when he says that linguistic rules are not represented in the mind, what he means is that the rules developed in linguistics describe constraints on language, without directly corresponding to how the brain actually handles language.

He's not saying that the mind does not have a language capability; it does, according to him. He's just saying that the structure of language described in linguistics is not part of the computational process the brain uses for language.