"Kiwi" is a common nickname for people from New Zealand. The official language of New Zealand is English, although Māori is also an official language and is widely spoken.
It's possible you're thinking of something else. Can you provide more context? For example, are you asking about:
* The Māori language? This is a Polynesian language spoken by the indigenous people of New Zealand.
* A slang term used in New Zealand? There are many slang terms and phrases used in New Zealand, but "Kiwi" itself doesn't refer to a specific language.
* A fictional language? There are many fictional languages created for books, movies, or games.
Please provide more details about what you're looking for.