Fragments (“Your ticket, please!”) can communicate the same meaning as a
full sentences (“Show me your ticket, please!”) do. But why and when do
we use fragments? We hypothesize that, following Levy & Jaeger's (2007)
Uniform Information Density hypothesis, specifically those parts of the
utterance which are predictable are omitted. We addressed this with a
rating study that shows that fragments are relatively preferred if they
refer to an event which is likely given the previous ones in a
script-based context. The rating study is complemented with a production
study that confirms our utterance likelihood estimates.