Can LEGO Boost play custom audio files? Can LEGO Boost play custom audio files on the Boost app from files kept on the device such as those downloaded from iTunes or transferred from a computer?

Are recordings from the tablet the only way to use custom sounds?
As far as I can tell, recordings from the tablet are the only way to use custom sounds at the moment. I imagine that the UI for a feature like this was deemed too complex for an app designed for children under 12. However, this should be easy to add to the app in a future update if there is demand for it.
One obvious workaround for this is to play the desired sound on another device and save it using the recording interface:

These recordings are limited to about 5 seconds.