Brazilian Portuguese Grammar

noun + preposition + noun		The first element goes to the plural
o pão-de-ló => os pães-de-ló *the spong cake => the sponge cakes* o leão-de-chácara => os leões-de-chácara *the bouncer => the bouncers (security guards)* a língua-de-sogra => as línguas-de-sogra *the paper serpent => the paper serpents* If the second element isn't a preposition, the third element goes to the plural: o bem-te-vi => os bem-te-vis *the great kiskadee => the great kiskadees*
noun + noun, in which the second element specifies the kind of thing the 1st element is.		Both elements or the only the first element goes to the plural
o pombo-correio => os pombos-correios or os pombos-correio *the carrier pigeon => the carrier pidgeons* a palavra-chave => as palavras-chaves or as palavras-chave *the key word => the key words* a banana-maçã => as bananas-maçãs or as bananas-maçã *the silk banana => the silk bananas*
onomatopoeic compounds		The second element goes to the plural
o tique-taque => os tique-taques *the tick-tock => the tick-tocks*
verb + verb compounds		Both elements or only the second element goes to the plural.
o corre-corre => os corres-corres or os corre-corres *the hustle and bustle* However, if verbs in compounds have opposite meanings, the compounds remain invariable in the plural: o vai-volta => os vai-volta *the coming and going*