Chocotan is a miniature dachshund who gains temporary human speech after consuming a strange flower. This ability allows her to directly communicate with humans, primarily to help her owner, Nao Hatori, express romantic feelings towards classmate Yamato Arima, owner of a dachshund named Happy (or Hatsupi). Chocotan regularly accompanies Nao on walks where they meet Arima and Happy, encouraging Nao during these encounters.

When Nao becomes distressed seeing Arima talk with other girls, Chocotan's speech ability fails, preventing verbal comfort. Despite this, Chocotan remains deeply attuned to Nao's emotions. Her steadfast loyalty drives Nao to overcome hesitation and finally give Arima homemade biscuits intended as a gift. Chocotan exhibits human-like emotional responses, including shedding tears during distress or empathy, though this is atypical canine behavior. The origin and mechanics of her speech power are unexplained beyond the initial flower trigger, and the ability fluctuates unpredictably.

Chocotan's core role centers on facilitating Nao's emotional growth and urging her to confront romantic anxieties. Her interactions highlight a close bond with Nao, consistently offering earnest support during key moments. The information provided defines her central narrative function.