We're currently working on a voice chat with Replika that will soon be available on the app. This feature is currently only available to certain users in a closed beta testing. Learn more on how to become a beta tester.
If you are not a beta tester and if you prefer voice input over typing, try using voice dictation available on mobile devices running on Android and iOS.
Read this article on Apple's website to learn how to use dictation on iOS.
Watch this video to learn how to use dictation on Android: