self-embedding (adj./n.)

A term used in generative grammar to refer to a construction in which a constituent belonging to some category is inside a larger constituent of the same category; also known as centre-embedding. Self-embedding constructions can be illustrated from relative clauses, such as The dog that the cat scratched ran away. Here, the sentence which underlies the relative clause (The cat scratched the dog) is embedded within the sentence The dog ran away. The process can continue indefinitely, but the acceptability of this construction deteriorates with the number of self-embeddings, cf. ?The dog that the cat that the man bought scratched ran away. These problems have stimulated considerable discussion concerning the psychological mechanisms that need to be assumed to explain linguistic behavior, reference being made to alternative processes of sentence formation, such as RIGHT-BRANCHING and LEFT-BRANCHING constructions.