Yes, after the first set-up — if your phone can recognise speech offline.
To set up, once: the words are downloaded. After that lessons work offline, but the app needs a connection from time to time — to download the paintings of the words coming next, and, if you are signed in, to sync your progress with our server.
Without a connection a lesson opens only if your phone can recognise speech offline — if it can't, the app tells you so before the lesson starts.
