oa Zinslengte en zinscomplexiteit

Stylistic advice concerning sentence complexity is often phrased in terms of sentence length. This paper examines the relations between sentence length on the one hand and structural complexity factors such as subordination, adverbial modifiers, noun phrase modifiers, coordinated constituents and dependency lengths on the other hand. The data come from an automatic analysis of about 40.000 sentences, taken from ten text genres.

Most genres have mean sentence lengths between 14 and 17 words; the only exceptions are textbooks for vocational schools (10 words) and scientific articles (24 words). Sentence lengths vary enormously within genres and within texts, casting doubt on the usability of sentence length advice. Subordinate clauses are frequent, but multiple subordination within a single sentence is not. Extra propositions can be built into the clause via adjectival and adverbial modifiers and coordination. The number of propositions per clause differs considerably between genres, much more so than the number of propositions per word (so-called propositional density). The final feature is the maximal grammatical dependency length in the sentence. Maximal lengths of more than 10 words are infrequent in simplex sentences, but regularly occur in complex sentences.

Taken together, the complexity factors explain much of the sentence length variance, but conversely sentence length does not strongly predict the occurrence of particular complexity factors. In diagnosing sentences, we should use complexity factors instead of sentence lengths. On a more general note, it remains to be seen to what extent structural complexity adversely affects comprehension, as larger grammatical structures may also help readers to synthesize propositions.