Code an example with audio recordings of speech, e.g., sentiment analysis

[Mikolaj]

Audio data is much smaller than video and probably also than photos, so there's a chance this fits CPU processing. Being ~linear~[edit: sequential], this may be a good fit for RNN [edit: recurrent neural networks], which is particularly well supported by our library and probably does not benefit from C libraries beyond lapack/blas. Given that, we may try to reach close to state of the art here, filling any gaps in our library that become apparent.