Children's acquisition of emotion words is a topic of interest across the domains of emotion research, early language acquisition, and social development. Prior research has shown a slow, gradual process of emotion word acquisition during ages 2–5 years and beyond. However, this research has used tasks that are demanding for young children, such as asking them to label or sort facial expressions. Here, in a preregistered study, we used a child-friendly looking-time paradigm---the "looking-while-listening'' task---to assess children's understanding of four emotion words, "happy,'' "sad,'' "angry,'' and "scared.'' We presented 64 two-year-olds (Mean age = 2.51, range: 2.00-2.97) with facial expressions and measured their preferential looking to the target face upon hearing an emotion word. Both younger and older two-year-olds showed above-chance performance when the target and distractor faces differed in valence (e.g., happy vs. sad). When the target and distractor faces were of the same valence (e.g., angry vs. sad), younger two-year-olds' results did not reach significance, but older two-year-olds' results were significantly above chance. These results suggest that within-valence mappings of emotion words to facial expressions emerges at least during the second half of age two. Full paper here: [https://osf.io/preprints/psyarxiv/nsq5t].

In many cultures, adults use simple, slow, and dynamic speech when talking to infants ("parentese," or infant-directed speech) and make expansive, repetitive movements when demonstrating object properties to infants ("motionese," or infant-directed actions). These modifications enhance infants’ attention to and learning about language and goal-directed actions. Adults’ interactions with infants are also full of emotions—do adults also modify their emotional expressions when interacting with infants? Here we showed parents of infants (aged 7 to 14 months; N = 25) emotion-evoking pictures including colorful bubbles, adorable stuffed animals, yummy snacks, broken toys, dangerous fire, and rotten fruits. We asked parents to describe their feelings about these pictures either to their infant or to an adult partner (i.e., an experimenter). While the parents’ use of emotion words did not differ between conditions, their emotional expressions did: Their infant-directed emotional expressions were more positive when they discussed positive pictures and more negative when they discussed negative pictures compared to their adult-directed emotional expressions. These findings suggest that besides "parentese" and "motionese," there is also a unique form of emotional communication in parent-child interaction—"emotionese."