Samsung Text-to-Speech became unavailable

With the Android 15 update, Samsung changed its policy, restricting Samsung TTS voices to their own apps. As a result, Lexilize Flashcards and other third-party apps can no longer use the Samsung TTS.

We recommend exploring alternative text-to-speech engines available on Google Play or other app stores.
Google text-to-speech module, you can download/update on Google Play by this link.

For more details and user discussion, see this Samsung community thread