Fascinating. I've always wanted to take part in one of these expeditions to record an endangered language. It's great the RPi is being used for so many things.

highly recommend a book called 'The Last Speakers' by K. David Harrison

Nicholas Evans' book "Dying Words" is also a very good read.

Thank you for the recommendations :)

What are the risks to using a system like this?

Is it possible that the feedback loops they have built the system into could actually degrade the data being collected?

Yes, a feedback loop could result in nonsense data being added to a corpus. This is one of the reasons that it's important to consider these sorts of technologies as not replacing a language speaker in a learning context, but being used in support of a person who knows the language. It's a concern even with keyboards for Indigenous languages - how much can people misusing a keyboard (intentionally or otherwise) influence language?