[zeteo]

Agreed about Vietnamese, which brings up another issue: diacritics. A word or phrase that is heavy on uppercase with diacritics ("BÁNH CUỐN") will look quite different in the vertical plane from one with a lot of descenders ("eggnog"). Even for developers who don't worry about Vietnamese, it is quite common in North America to require support for Spanish and/or French, which can also feature a lot of words with diacritics: "¿Ándale, vamos?"