Weird, isn't it?? But in fact, the translations are fine. Languages evolve in such an odd way....
This is not the only case where some words switch or invert meanings between English and Brazilian Portuguese.
But in Portugal, they are not inverted in this case. So I think Brazil was the one who mixed things up here :p
Not really! In fact, for my native ear, "celebração" is much more formal than "comemoração".
"Celebração" is related to ceremonies, church services, etc. "Comemoração" is what common people do together when they are happy.
It's weird how the meanings got "crossed" between the languages:
celebration = comemoração commemoration = celebração
Oh okay, it is probably a difference between Mozambique and Brazil, here they use "Comemoração" for times such as when they are celebrating the life of someone at their funeral. While I know "celebração" they use for both church ceremonies, but also parties such as weddings, graduations, and the like. More of the happy occasions.
I have realised that Portuguese in Brazil, Portugal, and Africa are different in many ways, including the meanings of words.
In Portugal, the use of the words is aligned with the English usage. So "celebração" means celebration (a happy event / party), while "comemoração" means commemoration (a more formal event e.g. remembering historic events like the end of the second world war).
For example, it is common in Portugal to say "celebração do aniversario" for birthday party, and "celebração do aniversario de casamento" for wedding anniversary.
So it seems that the crossing of the meanings is from the evolution of European Portuguese to Brazilian Portuguese...