> Below is a list of some known non-speech sounds, but we are finding more every day. Please let us know if you find patterns that work particularly well on Discord! [laughter], [laughs], [sighs]....

This is likely a reflection of the data used to train the model - TTS models are trained on labeled audio, one form of which is subtitled audio streams. In subtitles / closed captioning, bracketed words are frequently used when there is something audible that is not speech.

Based on this insight, it should be possible to inspect the training data and extract a set of non-speech sounds the model is likely to generate well - but that doesn’t drive engagement of your users like asking them to experiment themselves does ;)

For example, closed captioning adds music notes (♪) when music plays or when people sing. According to the Bark docs, adding ♪ causes the model to output things as music.