Your device reads the word aloud and you type it. Hear it again, slowly, or in a sentence any time. Ten words a round.
This game uses your device's built-in voice, so the accent and quality vary between phones, tablets and computers (Chrome and Edge tend to sound best). If your device has no voice at all, the game switches to showing the sentence with the word blanked out instead. Either way, typing a word from memory is the gold-standard way to practise spelling.