To date, very few studies investigating prosody its use in spontaneous speech. This dissertation examines prosodic use between friends and non-friends, as well as expert and novice dyads in a photography task. The main objective of the study was to examine if common ground units could be reliably predicted from prosodic variables, including break indices, boundary tones, and the timing of common ground units relative to preceding and following discourse. An additional objective was to examine whether potential differences were a function of relationship type or expertise level.

Twelve twelve dyads participated in the study. Using a 2x2 quasi-experimental design, with relationship type (friend vs. stranger) and expertise level (high vs. low experience) as the between-subject factors, the results indicated that all of the prosodic parameters could reliably distinguish simple common ground sequences from complex common ground sequences. Overall, there were stronger effects for response phase contributions, particularly with respect to timing variables. For the between-subject factors, being a stranger and having photographic expertise had the largest effects, with placement of common ground contributions the most consistent predictor.

In the discussion, several extended examples of common ground sequences are provided, illustrating how prosody and timing are used in discourse to achieve further grounding and facilitate communicational understanding. Implications for future research are presented, focusing on the ways the interpersonal communication researchers could make use of prosodic and common ground analyses in their own research.