Sock Puppets is a creation app that records voices, scrubs them, and creates a video. It is so easy (literally) kindergartner can do it. I have also had a lot of fun with high school students using this app. Videos are created by choosing your characters, props and scene. Start recording and then tap on each character as you want him or her to speak. When you are done, press stop and then save and/or share via YouTube or Facebook.
I like to use this app with Spanish students because they can talk and be silly without feeling self-conscious. Sock Puppets changes students' voices to cartoon voices, making it so engaging. If you are trying to assess pronunciation or speaking, you can tweak the voice settings to make it more accurate.
This is a great storytelling app that could be used with any subject, by any age. Examples might be a role-play story, a skit in a foreign language classroom, or even an explanatory video.