Congrats on shipping! I'm curious to know if kids in this demographic (2-6) see any extra benefits to something structured like this versus just watching cartoons in their target language? I've met plenty of people that have told me something like "Oh, I learned English from just watching Scooby Doo as a kid". They then went on to study English more formally in school when they were older, but they really claim they just learned from passively watching hours of cartoons on their own as a 3-6 year old, since that's what they had in their country of origin.
Cartoons can also be beneficial. We've discussed various techniques with two experienced speech therapists, each with their own beliefs shaped by years of working with children facing language disorders or expat families encouraging their kids to speak.
One specialist advised limiting cartoons to a maximum of 20 minutes per day, while the other suggested cartoons could be quite effective. I believe expert opinions should vary depending on the case.
In general, I think Voiczy can have a greater impact than simply watching cartoons. When playing a game, children are more engaged, focusing on learning words to advance through the levels. This can motivate them to pay closer attention. While cartoons can help with listening and understanding concepts, they may not be the best option for developing speaking skills, as they don't offer much practice.