According to what it hears from girls, Mattel's number one request is for a two-way conversation with Barbie. To meet this demand and capitalize on the growing market for conversational tech, the company partnered with startup ToyTalk in 2015 to create the "Hello Barbie" doll, which had hardware embedded in its body that enabled it to engage in conversation using artificial intelligence and natural language processing. Like other conversational technologies such as Siri, Barbie had a default response for unexpected questions or statements: "That sounds like something you should talk to a grown-up about."

The AI doll was among the first sophisticated consumer products for young children in the growing…