A free app for Android, by GuoShi.
Text Talk is an easy to use application that allows you to input a sentence and let Alexa talk to you.
The main differences are that the app supports more languages, has a premium version, and has an ad-free, premium version. The free version is limited to English.
In addition to supporting English, the app also supports Spanish, French, Italian, Japanese, and some other languages. The app also allows you to adjust the speed of the speech and the pitch. The audio can also be saved to your device.