Two other intelligent alien species that exist in the universe: Yebadeba/Novastellarians and Epama/Arthropedians.
Novastellarians are the largest known sapient creatures at 8 to 9 feet tall. They have no vocal language, instead using their tentacles for an elaborate sign language. They're very gregarious, and considered quite chaotic and aggressive by Mareinian standards.
Arthropedians are much smaller at around 4 feet tall. While they do have a vocal language, it's quite unique–consisting of words overlaid with a high-pitched humming. Not only is this language completely impossible to speak for every other sapient species, but Mareinians can't even hear their humming. Instead, Arthropedians replace the humming with their own sign language (much simpler than the Novastellarian language) when speaking with offworlders. Their culture is quite religious and they tend to stay in the area they grew up in, meaning they are a rare site outside of their home planet.