Having never formally studied any Chinese languages I surmised that the word “oolong” was the proper English transliteration of the Mandarin Chinese name for a family of teas and that “wulong” was a word that had come into vogue for use in preposterous and unfounded weight-loss claims in order to promote Chinese oolong teas. While “wulong” is the more common choice in deceptive marketing materials and by sensationalist talk show hosts, ironically it is the correct word in Pinyin (the official Romanization system for Mandarin Chinese). The source of “oolong” is the Wade Giles system, which has largely been supplanted by the Pinyin in recent years. The Mandarin characters for wulong tea are: 烏龍茶, the first two characters representing the syllables “wu” or “oo” and “long” respectively. The third character represents “cha” the Mandarin word for tea. Getting a consistent answer as to the one true Pinyin word is even a challenge. It appears frequently as “wulong,” wu-long,” and “wu long” and in more precise usage includes diacritical markings, making it “wūlóng.”
If you see Chinese words that are spelled differently from the Pinyin standard, they were probably imported into the English speaking world via Taiwan, or else they have been in use since before Pinyin was common. It is also possible that they came from another another language, such as Cantonese or Japanese.
– from this article on the topic on the
Tea From Taiwan site
Of course we get into a little bit of a tangle about which word to choose when it is commonly understood that the word in English is “oolong.” So then you have to decide if the English word “oolong” or the Pinyin Chinese word “wulong” better suits your purpose. There is a very fine line between using the antiquated form of Wade Giles “oolong” and the English word “oolong.” This whole discussion may be dismissed as self-indulgent sophistry, but regardless of which words you choose yourself to refer to those fabulous semi-oxidized teas, the history behind the jumble of choices is pretty interesting.