The machine language is a writing system and, perhaps, a fully functional language seen throughout Girls Last Tour and Shimeji Simulation. It is written as concentric line structures with occasional fish images.
Not much is known about it, there is no official decryption available and no fan ones are known. It is not clear if it's really a writing system at all, but it must be.
It seems that the machine language is more complex in ShimSim, because of the inclusion of fish and other graphical elements that are not found in GLT.