Well, the idea was to create the most efficient and compact language for humans to use. Having a species with 3000 vocal chords and 30 arms for a bonus sign lan

Well, the idea was to create the most efficient and compact language for humans to use. Having a species with 3000 vocal chords and 30 arms for a bonus sign language elements would be easier to work with, but wouldn’t be usable by humans. And as in my previous comment, languages for non-humanoid species do exists if someone prefers to go in that direction. Similarly, toki pona was designed to contain only the most popular phonemes among human languages, because it was designed with humans in mind. Edit: I should stop starting the comments with “well”, shouldn’t I? :P Edit 2: The “spoken” aspect can be similar to why we use CSV and TSV file formats, while even ASCII had from the beginning assigned characters for record delimiter — humans grasp easier thinks they can see/hear.