Rhythmic alternation and the optional complementiser in English: new evidence of phonological influence on grammatical encoding.

In a recall-based spoken production experiment, native English-speaking participants' variable use of the complementiser that to introduce the sentential complement in sentences like Henry knew (that) Lucy/Louise washed the dishes was found to be related to whether that inclusion/omission resulted in an alternating sequence of stressed and unstressed syllables between the verb of the main clause and the subject of the complement clause. This finding is discussed in relation to the question of whether and how phonological encoding can influence grammatical encoding in spoken language production.