One character, two pronunciations
The Chinese character 茶 is read differently across Chinese varieties. In Mandarin and Cantonese and across most of the country it is chá. In the Min varieties of the southern Fujian coast — the ports European traders actually used — it is closer to tê. That single split accounts for nearly every word for tea in the world. There is no third family of any size, and the handful of exceptions are informative rather than awkward.
Cha travelled overland; te travelled by sea
TeaHQ's own reading of well-attested general knowledge, with no single source behind it.
The chá form went out along the land routes — north and west across Central Asia, into Persian, Arabic, Turkish, Russian, Urdu, Hindi and onward into Swahili and much of eastern Europe. Chai, çay, shay, chay: all the same word with local sound changes, and all reaching their destinations across land over a long period. The tê form went by ship. Dutch traders bought at the Fujian ports where that pronunciation was current and carried both the leaf and the word into Europe. Dutch thee gave English tea, French thé, German Tee, Italian tè, Spanish té and the Scandinavian forms. The English word arrived on a Dutch ship, which is why English and Russian — two languages whose speakers drink comparable amounts of the stuff — do not share a word for it.
Where the pattern is visible on one map
Turkey says çay and Greece says tsái, both by land. But Greece also has a te-family term in some registers, because sea trade reached it too. Portugal is the striking European exception: chá, not té. Portuguese trade ran through Macau, where the Cantonese chá is spoken, rather than through the Min-speaking Fujian ports the Dutch used. One country's word records a different port. Japan and Korea both say cha and neither got it from a trade route — they received tea directly from China centuries before any European ship was involved. Poland says herbata, which looks like neither. It is from Latin herba thea, the botanical name, and is a reminder that a few languages acquired tea through pharmacy and scholarship rather than through commerce.
What the split is useful for
TeaHQ's own reading of well-attested general knowledge, with no single source behind it.
It is a reliable, checkable shortcut for how tea reached a place. A language with a cha-word almost certainly met tea overland and early; a te-word means a European maritime trade route and, usually, the seventeenth century. It also disposes of a common confusion. "Chai" in English now means spiced milk tea, which is a narrowing that happened in American and British cafés. In Hindi, Urdu, Russian, Turkish and Swahili the word simply means tea. Ordering a "chai tea" is, etymologically, ordering a tea tea — which is not a reason to correct anybody, and is a reasonable thing to know.