The role of production processes in determining word duration

Vanderbilt University, Nashville TN

Investigators

Abstract

The rhythm and timing of our speech plays an important role in communication. For example, speakers tend to say the word nine more quickly in the sentence A stitch in time saves nine than in the sentence The number I am thinking of is nine. Some of these differences in timing are driven by our desire to help the listener understand us: the word nine is less predictable in the second sentence than it is in the first, so we lengthen it to give our listeners extra time to understand it. Alternatively, speakers may shorten nine in the first sentence because it is easier to say. Slowing down and speeding up during speaking may give the production system the time it needs to plan and produce accurate, continuous speech. This project examines the types of planning that occur during speech and the different ways they may affect our speaking rate. The results of this project may eventually lead to better interventions for individuals with speech disorders and to advances in designing artificial speech systems that sound more natural. A puzzle for language researchers is understanding the factors that affect how speakers actualize specific words. For example, the length of a given word is driven, at least in part, by how informative the word is in the discourse (e.g., how predictable it is, how much new information it provides, etc?). What is less well understood are the specific factors and mechanisms that underlie the timing and duration of each word. This project tests the hypothesis that different levels of linguistic planning have differential effects on time to articulation and word duration, a theory the investigator calls the ?two-domain hypothesis.? Under this hypothesis, lexical and conceptual planning influence the time to begin articulating a word, while planning processes related to phonological ordering affect the timing of producing the word itself. Preliminary work suggests that when the process of encoding the order of a word?s sounds is complex, the word is lengthened. On the other hand, when this phonological encoding proceeds smoothly, the word is shorter. Preliminary experiments also suggest that lexical priming affects the time to begin a word?s articulation, but not the word?s duration. The proposed experiments use an event-description paradigm to test the predictions of the two-domain hypothesis and will lead to a better understanding of which aspects of planning influence word duration.