Chinese language
The Chinese language was an Earth language spoken in China and other areas with large Chinese populations, such as San Francisco's Chinatown. It consisted of numerous spoken varieties, such as Mandarin Chinese and Cantonese, that shared a common writing system. (; ; )

When the universal translator on the  malfunctioned, one of the many languages the system translated verbal and written displays into from Federation Standard was Mandarin Chinese. () 

As the first and potentially only Kelpien to enter Starfleet, Saru felt pressure to over-perform at Starfleet Academyand in his career. By 2257, he understood 94 languages including English, Chinese, Wolof, Spanish, and Russian. ()

Madame Chang's Mandarin Cafe  had a bilingual English and Chinese sign outside it. ()

Appendices

Background information
In devising the Tamarian language,  writer Joe Menosky was inspired by the dense historical metaphors present in Chinese language poetry and philosophical works such as the . (Star Trek: The Next Generation 365, p. 220)

SF Debris theorizes in his video "The Language of Darmok" that "metaphor" is likely not what is really going on with the Tamarian language by using Chinese as an example. He explains that in Hanzi, the Chinese system of writing, the word for China is comprised of two ideograms: 中 ("middle") and 国 ("nation" or "kingdom"). The second character itself is comprised of two radicals, 玉 ("Jade" or "precious gem") and 囗 ("enclosure"). Given the universal translator does a word-by-word translation, SF Debris says this means if the translater were to be given the term "中国," rather than return "China" or "Middle Kingdom," it would probably produce the somewhat nonsensical "central enclosed jade".

External links
 
 

Earth languages