According to Jim

S01E11 The Bad Word

Cheryl entrusts Jim with their children and a few friends while she enjoys a Bears game. The following day, Cheryl receives a call from one of the children’s mothers, informing her that her daughter has come home echoing a swear word she picked up from Jim. Cheryl apologizes, but Jim feels slighted that she always sides with others. After Cheryl expresses her regret, Grace unexpectedly repeats the same profanity. In an attempt to curb her language, Jim makes her say it repeatedly until she can no longer utter it. However, days later at Ruby's ballet recital, she falls and inadvertently blurts out the word, exposing Jim's culpability.