My Brazilian informant tells me there is no word in Portuguese for "frown". I'm astonished -- it's part of the basic conceptual inventory of opposites of any English-speaking three-year-old (big/little, black/white, yummy/yucky, smile/frown, etc.). I'd have assumed it was a human universal. Not at all, says my amiga carioca.
My dictionary says that a frown in Portuguese is um cenho, but my informant says nobody uses that word and when she mimes it she does more of a grimace than a simple frown anyway.
The Corpus Lingüisticus Googleeënsis confirms her report. Google searches of Portuguese pages turn up a mere 1210 hits for cenho while sorriso (smile) occurs 140,000 times. That's a smile/frown ratio of 116 : 1. The same ratio for English is just 15 : 1. I found similar results for laugh/frown ratios. I'm no statistician but the difference looks significant to me. (Curiously, in Spanish there are more frowns even than in English: the sonrisa/ceño ratio in Spanish is a mere 9 : 1.)
I jokingly suggested to my Brazilian friend that there's no word for frown because everybody in Brazil is too happy. She said she thought it must be true. I want a National Institute of Mental Health grant to study the matter further.