Does speaker emotion affect degree of ambiguity in referring expressions? We used referential communication tasks preceded by mood induction to examine whether positive emotional valence may be linked to ambiguity of referring expressions. In Experiment 1, participants had to identify sequences of objects with homophonic labels (e.g., the animal bat, a baseball bat) for hypothetical addressees. This required modification of the homophones. Happy speakers were less likely to modify the second homophone to repair a temporary ambiguity (i.e., they were less likely to say … first cover the bat, then cover the baseball bat …). In Experiment 2, participants had to identify one of two identical objects in an object array, which required a modifying relative clause (the shark that's underneath the shoe). Happy speakers omitted the modifying relative clause twice as often as neutral speakers (e.g., by saying Put the shark underneath the sheep), thereby rendering the entire utterance ambiguous in the context of two sharks. The findings suggest that one consequence of positive mood appears to be more ambiguity in speech. This effect is hypothesised to be due to a less effortful processing style favouring an egocentric bias impacting perspective taking or monitoring of alignment of utterances with an addressee's perspective.