Hi Malcolm.
If you use the web address on the line below in your browser ...
http://www.etymonline.com/index.php?term=tea
... it explains some of the background to the word 'tea'.
The entry of that website starts:
"1650s, earlier chaa (1590s, from Port. cha), from Malay teh and directly from Chinese (Amoy dialect) t'e, in Mandarin ch'a ..."
JimC