This study investigates the relation between vowel identity and emotional state. In Experiment 1, (pseudo)words were invented and articulated in a positive or negative mood condition. Subjects in a positive mood produced more words containing /i:/, a vowel involving the same muscle that is used in smiling--the zygomaticus major muscle (ZMM). Subjects in a negative mood produced more words containing /o:/, involving an antagonist of the ZMM--the orbicularis orbis muscle (OOM). We argue that the link between mood and vowel identity is related to orofacial muscle activity, which provides articulatory feedback to speakers on their emotional state. Experiment 2 tests this hypothesis more specifically. Participants rated the funniness of cartoons while repeatedly articulating either /i:/ (ZMM) or /o:/ (OOM). In line with our hypothesis, the cartoons were rated as funnier by subjects articulating /i:/ than by those articulating /o:/.