Why Subject Relatives Prevail: Constraints versus Constructional Licensing

Relative clauses containing subject relative-pronouns are the prevalent type both across languages and in conversation, accounting for 65% of relative clauses in the American National Corpus (Reali and Christiansen 2007). This fact appears attributable to processing constraints, as per Hawkins 1999, 2004: subject extractions are the most local filler-gap dependency and therefore impose the least burden on short-term memory. This processing explanation, however, not only lacks strong psycholinguistic support but also fails to explain a major pattern in English corpora: subject relatives are the preferred modifiers only of object nominals. We propose that this preference is driven not by general-purpose interpretive or encoding constraints but by constructional licensing: the subject relative is part of an entrenched syntactic routine, the Presentational Relative construction (McCawley 1981, Lambrecht 1987, 1988, 2002). We investigate this hypothesis by examining the formal, semantic and pragmatic properties of relative-clause modifiers of object and oblique nominals in an English conversational corpus. We find that the subject relative-clauses within this set display significantly more hallmarks of presentational function than do their nonsubject counterparts. We conclude accordingly that the prevalence of subject relatives is a reflex of the role that this pattern plays in a frequently used construction, rather than constraints that rule out other relative-clause patterns.