Scope of Message Planning: Evidence From Production of Sentences With Heavy Sentence-Final NPs.

Speaking begins with the generation of a preverbal message. While a common assumption is that the scope of message-level planning (i.e., the size of message-level increments) can be more extensive than the scope of sentence-level planning, it is unclear how much information is typically encoded at the message level in advance of sentence-level planning during spontaneous production. This study assessed the scope and granularity of early message-level planning in English by tracking production of sentences with light versus heavy sentence-final NPs. Speakers produced SVO sentences to describe pictures showing an agent acting on a patient. Half of the pictures showed one-patient events, eliciting sentences with unmodified patient names (e.g., "The tailor is cutting the dress"), and half showed two-patient events with a target patient and a non-target patient. The presence of a non-target patient required production of a prenominal or postnominal modifier to uniquely identify the target patient (e.g., "The tailor is cutting the long dress" / "the dress with sleeves"). Analyses of speech onsets and eye movements before speech onset showed strong effects of the complexity of the sentence-final character, suggesting that early message-level planning does not proceed strictly word by word (or "from left to right") but instead includes basic information about the identity of both the sentence-initial and sentence-final characters. This is consistent with theories that assume extensive message-level planning before the start of sentence-level encoding and provides new evidence about the level of conceptual detail incorporated into early message plans.