What is the Middle chief language?

There's no language known as "Middle Chief Language." It's possible you're thinking of a different term or have a misunderstanding.

To help me understand what you're looking for, could you please clarify:

* What is the context? Where did you hear this term?

* What do you think it refers to? Do you have any idea what type of language it might be?

* Is there any other information you can provide? For example, is there a specific region or group of people associated with this term?

With more information, I can help you find the language you're looking for.