Working Memory Constraints on Multiple Center-Embedding

Working Memory Constraints on Multiple Center-Embedding Fred Karlsson (fgk@ling.helsinki.fi) Department of Modern Languages, PO Box 24 FI-00014 University of Helsinki, Finland (3) On March 13, [ C-1 when he preached a sermon on the text,] he told his congregation how disappointed he was (Brown). (4) For an analysis of the possible modifications [ C-1 of which the pathological termination of an act [ C-2 which is not according to law] are susceptible] we have therefore . (Jeremy Bentham) Abstract Gibson’s (1998) theory on the locality of syntactic dependencies claims that multiply center-embedded clauses are unacceptable if they contain a parse-state with at least two long unresolved predicted categories in addition to the top- level verb. ‘Long unresolved’ means a syntactic prediction spanning at least three intervening new discourse referents. This claim was based on experimental analysis of invented examples. Karlsson (2007b) provided corpus data demonstrating that, contrary to widely accepted views in linguistics and cognitive science, there are well-defined constraints on how many (maximally three) and what types of multiple center-embeddings occur in spoken and written discourse in natural languages. Gibson’s theory of the processing of multiple center-embeddings will be evaluated in the light of Karlsson’s empirical data. The corpus data do not support the idea of a discrete limit on working memory capacity, because almost one third of the extant examples of multiple center-embedding are more complex than Gibson’s acceptability limit stipulates. Spoken language processing complexity is clearly below Gibson’s limit, written language is capable of transgressing it. When a sentence contains multiple embeddings of the same type, e.g. two center-embeddings as in (4), the DEGREE OF EMBEDDING is equal to the number of embeddings and occasionally indicated by the character ‘C’ superfixed with the degree. Thus, (4) is an instance of C 2 , double center- embedding. A clause embedded after the initial subordinating (or coordinating) conjunction of the superordinate clause is not center-embedded but initially-embedded, e.g. the I-2-clauses in (5, 6): (5) [ I-1 If [ I-2 what is tantamount to dictatorship . ] continues in a union] it can . (Lancaster- Oslo/Bergen Corpus = LOB)) (6) c. [ I-1 If [ I-2 when I’m 38] Metallica ends] I don’t think . ] (British National Corpus = BNC) Keywords: center-embedding; clausal embedding; cognitive explanation; complexity; embedding; multiple center- embedding; recursion; syntactic complexity. Definition of Center-Embedding The notion EMBEDDING refers to all types of clauses occurring as subordinate parts of their superordinate clauses (which themselves may be either main or subordinate). The starting point will be the classical view of subordination as expounded in Quirk et al. (1989, Chapter 14). Typical finite sub-clauses are of three types: complement, relative, and adverbial. They are indicated by subordinators or relative pronouns, henceforth called sub/wh-elements. C ENTER - EMBEDDED clauses have words of the superordinate clause both to their left (excluding subordinators and coordinators) and to their right, as the relative clauses in (1, 2) and the when-clause in (3). S ELF - EMBEDDING is multiple center-embedding invoking two or more clauses of the same type, e.g. two relative clauses as in (4). In the examples, the gross clausal structure is indicated by angular brackets prefixed by the character ‘C’ for center- embedding and an integer indicating dept of embedding. (1) Others [ C-1 who are attracted to this Mecca of the beat generation] are heroin addicts and small hoodlums. (Brown Corpus) (2) Another frequent pioneer difficulty, [ C-1 caused by wearing rough and heavy shoes and booths,] was corns (Brown). Here, the subordinating conjunctions of the respective I-1- clauses are not fully integrated syntactic constituents in their clauses and therefore a further clause embedded after them is not center-embedded but initially-embedded. The superordinate clause material preceding a center-embedding must consist of full syntactic constituents, as in (1-4). Empirical data on multiple center-embedding By systematically searching the Brown and LOB corpora, by checking the extant scarce empirically-minded literature on multiple center-embedding, by consulting more than 100 older grammars, style manuals and philological studies especially of older forms of German and Latin, and furthermore by manually analyzing 6000 sentences by three 19th century scholars known for their intricate and syntactically complex language use (Jeremy Bentham, John Stuart Mill, C. S. Peirce), Karlsson (2007) established a data pool of 13 triple center-embeddings, C 3 , and 104 double center-embeddings, C 2 . As every C 3 contains two C 2 s, the total number of C 2 s is 130. The languages concerned were English, German, Latin, Swedish, Finnish, French and Danish, from Antiquity to the 21 st century. Here are three of the C 3 s observed: