Zinslengte en zinscomplexiteit: Een corpusbenadering

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.