ABSTRACT
While there is no interesting limitation on the degree of right-embedding in acceptable sentences, center-embedding is severely restricted. Similarly, while there is no interesting bound on the number of nouns that can occur in acceptable noun compounds, there is a very low bound on the number of causative morphemes that can occur in the verb compounds of agglutinative languages. Turning to the clause-final verb clusters of West Germanic languages, we find another similar bound. A cluster including verbs from one embedded clause may be acceptable, but clusters formed from the verbs of two or three or even more deeply embedded clauses are much more awkward (regardless of whether the subject-verb dependencies are crossing or nested). And in languages that allow multiple wh-extractions from a single clause, extractions of more than one element with a given case quickly become unacceptable. More careful experimental study of the nature of these limitations is needed, in a range of languages, but here a preliminary attempt is made to subsume them all under a single generalization—a version of the familiar idea that the human parsing mechanism is limited in its ability to keep track of many grammatical relations of the same kind. To make this idea more precise, I assume in the first place,
Weak competence hypothesis: Human syntactic analysis typically involves the explicit recognition of all grammatical relations.
