I can’t say with 100% certainty that Voiczy is more valuable than Duolingo. Duolingo has years of experience and likely offers unique content—they're a large company with many resources.
However, Voiczy was born out of necessity. We tried Duolingo and other apps, but they didn’t suit our son’s needs. Every child has a different learning style. I encourage you to give Voiczy a try. We offer a 7-day free trial, and I’d be happy to extend it for you if needed. You can see if your son finds it helpful and let me know your thoughts & feedback.
What sets Voiczy apart is that we use the child’s native language to bridge the gap with the new words they're learning. This makes the process feel less pressured and more engaging and faster to grasp. That’s what we observed with both our son and beta testers.