Have you searched for the Lingokids app in Amazon Store and a message saying that it isn't compatible appears? 🤔
So the Lingokids app is actually unavailable on the Amazon Store. You must download Google Play Store on your Fire tablet and then, through there, download the app through Google Play.
You can check out these instructions here to install the Google Play Store on your Amazon tablet.
You can also search for other helpful articles in your preferred search engine for further options.
Let the playlearning™️ begin!