Goblins speak a high, rapid chittering language, with an incredibly diverse vocabulary and complicated grammatical structure that is almost impossible for non-Goblins to grasp, especially without a dedicated teacher. There are a dozen or more distinctly different ways to express even the simplest concept, while wildly disparate ideas may have only the subtlest of differences in expression.
With all of this said, it is not an especially precise language and it lacks any method to count past eight, to convey complex emotions, or to request, it can only demand. Ideas that might otherwise be carried by tone or word choice are stated outright, “I grovel before you oh great king, give me the crop report.” or “You are my friend, suck the poison out of my leg now.”
The written form of Goblin consists of long scribbles of hatch marks and scratches, and can be easily hidden or simply overlooked. It relates indirectly to the various screeches, squeaks and tones of the language.