What is the proper noun for Tibetan?

There isn't a single, universally accepted proper noun for "Tibetan" as a language. It depends on what you want to emphasize:

Referring to the language:

* Tibetan: This is the most common and straightforward term.

* Böd-skad: This is the name of the language in Tibetan.

* Bodish: This term is more academic and emphasizes the broader family of languages that Tibetan belongs to.

Referring to the people:

* Tibetan: This is the most common term for the people of Tibet.

* Bödpa: This is the word for "Tibetan person" in Tibetan.

Ultimately, the best term to use depends on the context and your audience.