A Re-examination of Syntactic Complexity by Investigating the Internal Structure Variations of Adverbial Clauses across Speech and Writing

This paper re-examines the debatable issueabout adverbial clause (A,CL) whether it indexes a complex discourse of contemporaryEnglish and how it distributes across Speech(S) and Writing (W) with different subtypes ofstructures by investigating the internal structure variations. A Finite-State-Machine modelis adopted for retrieving the internal structures. Empirical results show that A,CL prevails in W than in S with a higher occurrencerate (W: 31.20% vs. S: 14.80%), which confirms its function of indexing a complex discourse; but the standard token-type-ratio ofits internal structures shows an opposite distribution (W: 12.89% vs. S: 16.66%), whichsuggests a higher structural density/variationof the spoken mode; besides, five subtypesof internal structures are identified with various distributions across S and W: S employsa higher proportion of subordinator-overt subordinating A,CL, while W adopts more infinitive A,CL, including to-infinitives, presentand past participles; coordinated embeddingsand subordinator-covert finite A,CL are commonly found in both modes. Despite of theindividual variance of internal subtypes, statistical test indicates a less noticed fact that theoverall structural variation of A,CL between Sand W is not significant (p-value = 0.5245).