Dragon Dictation is a free voice-to-text app for iPhone and iPad. There’s an Android app called Dragon Mobile Assistant that appears to be the same/similar, is also free and is made by the same people, but I have not tried it. This is what the icon looks like:
With this app, you can recored your voice, then edit the text and copy it to another app, or share it via e-mail, Facebook or Twitter. It’s a very useful note-taking app, for when you have good ideas but no time to stop and write.
There’s a keyboard icon in the bottom left corner, so you can edit and add punctuation.
And you can change languages in the Settings. The default appears to be American English, but you can choose from about 30 languages, including Japanese. It’s a good test for your pronunciation, too.