Grammatical Saturation

(a) My letter to a friend in Italy got lost.
(b) *Who did my letter to get lost?
(c) *Gianni is the friend who my letter to got lost.
- Introduction to the Theory of Grammar, by Riemsdijk and Williams, p. 21
[The asterisks above indicate that the sentence is not grammatical.]

Judgments of grammaticality can be affected by repetition of non-grammatical sentences.

The ability of our brains to ignore sensations is amazing. People can get used to falling asleep amid the din of street traffic, or learn to ignore unpleasant odors they can't avoid. Also, there are optical illusions based on the physiology of the mental pathways used by our visual systems. Upon certain types of repetition, our brains can even diminish the degree to which meaning is associated with familiar words. That's right‒‒we can temporarily "forget" what words mean, leading to a lexical jamais vu. This phenomenon is known as semantic saturation. This post proposes a possibly related phenomenon in which people's internal rules of grammar can be similarly "forgotten" as a result of repetition. What is forgotten is not how to construct or identify grammatical sentences, but rather how to flag sentences as ungrammatical. If that seems strange or counterintuitive to you, you are not alone.

I once took a linguistics class that used the book Introduction to the Theory of Grammar, by Riemsdijk and Williams. For those unfamiliar with the study of linguistics, this might conjure up images of pages upon pages of sentence diagramming. But that isn’t what the text (or the course) was about. Instead, it sought to present "one current view about the nature of Universal Grammar", the underlying grammar shared by all human languages. Toward this end, it used sample sentences, both grammatical and ungrammatical, in English and other languages, to motivate and illustrate a model of the deep structure of human language.

I found that if I repeated some of the sentences that at first seemed ungrammatical, they started to sound grammatical. If I then focused on something else for a while, my linguistic sensibilities mostly returned to their original judgments. Was my inner grammar judging mechanism just taking a rest, or was I getting won over to a broader concept of grammar in which sentences like (b) and (c) quoted above are grammatical?

There doesn’t seem to be any research into this phenomenon. (But see [1].) I’ll call it grammatical saturation, since it seems similar to the notion of semantic saturation. (*) But whereas semantic saturation takes place at the word level, grammatical saturation takes place at the sentence level. Also, while semantic saturation makes a familiar word seem foreign, grammatical saturation makes a formerly jarring phrase or sentence seem acceptable. Semantic saturation is believed to be caused by reactive inhibition of the neural pathways that associate meaning with the word being repeated. Perhaps there is similar inhibition that can occur with the neural pathways used to identify a phrase or sentence as ungrammatical.

(*) Grammatical saturation as I have defined it here is unrelated to a similarly-named notion called syntactic saturation.

[1] Nagata, H. “Effect of repetition on grammaticality judgments under objective and subjective self-awareness conditions”, Journal of Psycholinguistic Research, 18.3 (1989), 255-269.

Epilogue

Here's an interesting anecdote from that linguistics class I took. For the most part, the English sentences in the course textbook that served as examples were either clearly grammatical or clearly ungrammatical. In addition, we discussed some other sentences in class that seemed grammatical to some of us, but ungrammatical to others. All twelve students were native English speakers from various parts of the United States. Many of these "borderline" sentences were deemed ungrammatical to all but two people in the class. I was one of them; the other was a woman who sat on the other side of the room. After several of these shared grammaticality judgments I introduced myself, and found that she grew up about six miles from where I did. In fact, I’d spoken with her on the phone about a year before when we were both halfway across the country.