[wizofaus]

"Taxi" is quite different in Chinese and Arabic for a start. I'd guess it's likely to be almost universally understood among all humans that have had exposure to the concept though.

[whitten]

I think taxi (spelled differently) is in Russian, Greek, and Spanish

[themoonisachees]

Taxi in Russian is indeed pronounced the same and is written Такси.

[spamtarget]

so no winner then?