Eye-tracking and gating experiments examined reference comprehension with fluent (Click on the red. . .) and disfluent (Click on [pause] thee uh red . . .) instructions while listeners viewed displays with 2 familiar (e.g., ice cream cones) and 2 unfamiliar objects (e.g., squiggly shapes). Disfluent instructions made unfamiliar objects more expected, which influenced listeners' on-line hypotheses from the onset of the color word. The unfamiliarity bias was sharply reduced by instructions that the speaker had object agnosia, and thus difficulty naming familiar objects (Experiment 2), but was not affected by intermittent sources of speaker distraction (beeps and construction noises; Experiments 3). The authors conclude that listeners can make situation-specific inferences about likely sources of disfluency, but there are some limitations to these attributions.