Palabras Ocultas (Hidden Words) generates grids of Spanish words for you to search. As well as spelling, words are spoken as you find them (or you can hear the Spanish to help you find the word. You also have the option to try to speak a Spanish word and have the game find it from your pronunciation.
The app will request the "Record Audio" permission. This is so that it can use Google Speech Recognition to allow you to search for words by speaking. The words you speak will be sent to Google to be processed into text. Speech recognition is only available when you have internet access.
The app uses your device's Android Text to Speech functionality to speak Spanish. This works offline, but you may need to be online for it to download the Spanish language files the first time (if your device doesn't have them loaded already). You can choose not to use this option if you prefer (or to turn it off if you want to play quietly).