'With the sound, we’re trying to paint a picture of what is Rocky's sonic soul.'

'Project Hail Mary' sound designers used surprising animal sounds to create Rocky's musical alien voice (interview)

Source: space
Source Link: https://www.space.com/entertainment/space-movies-shows/project-hail-mary-sound-designers-used-surprising-animal-sounds-to-create-rockys-musical-alien-voice-interview