What did a developer likely use to get his Alexa to speak through Big Mouth Billy Bass?

There's no indication from developer Brian Kane's video as to how he got Alexa to speak through his Big Mouth Billy Bass — a novelty item that sings and "dances" when its motion sensor is activated. But The Verge speculates it's likely related to the Alexa API, which was opened up in April and lets developers embed the smart assistant into third-party software.