Chatbot Lily stepped in for Luis von Ahn, the CEO of Duolingo, for opening remarks on Wednesday's earnings call.Screenshot from Duolingo earnings call and Kevin Dietsch for Getty ImagesDuolingo's Wednesday earnings call started with an AI chatbot demonstration.The chatbot, Lily, summarized the company's performance this quarter.Despite revenue growth, Duolingo missed paid user targets, and its stock fell 5% in late trading.Duolingo kicked off its latest investor call on Wednesday with a new voice: Lily, an artificial intelligence-driven chatbot based on a longtime app character.The purple-haired chatbot, which sounded like a bored, sarcastic teenager, replaced CEO Luis von Ahn at the beginning of the video call.