Walk into a branch of aglobal coffee-house chain and order a chai tea. Wait – you’re actually saying “tea tea”. The origins of these two words for the same drink reflect diverse trade routes and the transmission of tea-drinking culture.

While the tea plant’s habitat stretches from northeastern India to the east coast of China, and down into Southeast Asia, the steeping of its leaves in hot water to drink originated in China, circa 2700BC, with the practice spreading to Japan in about AD800. On the ancient overland Silk Road – starting from circa 1600BC, with large-scale trade from the 10th century – tea, and its northern Chinese name chá, were carried from China through Tibet, on to India, Central Asia and Eastern Europe. Adopting the Persian suffix -yi gave Persian chay, Arabic sha¯y, Turkish çay and Uzbek choy.

Tea was also transported on later European maritime trade routes. The 16th-century Portuguese tea trade had its source in Macau and Canton and took the similar form chàh, from Cantonese, subsequently spreading it to India.

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The 17th-century Dutch East India Company traders – early importers of the product to Europe – obtained their tea from Amoy, in Fujian, importing the word from the Amoy dialect of Minnan. This became Dutch thee (pronounced tay), and spread in similar form in the Dutch East Indies – for example, teh in Javanese – and across all languages of Europe (except Portuguese and Basque). English tea assumed its present-day pronunciation following an 18th-century sound change (altering the pronunciation of long vowels, with ay becoming ee).

In the early 19th century, to counter the Chinese tea-trade monopoly, the British East India Company started cultivating tea in Assam and, by the turn of the century, half of the tea consumed in Britain came from India. Tea consumption among locals as a recreational beverage was promoted by the Indian Tea Association in the early 20th century. Local vendors drew on the traditional practice of brewing tea as a herbal medicine, with Ayurvedic spice mixtures, thus estab­lishing masala chai – “spiced tea” – as a regular beverage.

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The word char/cha – as in “a cup of char” (reducible to “a cuppa”) – as this working-class drink was referred to in 19th-century colloquial British English, would have come from Hindustani char, likely introduced by British India ser­vice­men. Similarly, chai is dated to circa 1919 military slang. Masala chai is documented in English in 1977 – but gets clip­ped so chai in modern times comes to refer to the spiced version.

Ironically, while the term “milk tea” – the Hong Kong-style drink made with black tea and evaporated or condensed milk – was added to the Oxford English Dictionary in March this year, Hongkongers’ Cantonese term for milk tea, naai cha, from which char/cha originated, was not.