BlackZ wrote:By the way, each region has a different pronounciation for "rr" (and "r" in the beginning of the word) - [ʀ] Carioca, [r] Paulistano, [ɹ] Paulista, and many others.
Actually, the Carioca pronunciation of 'rr' and /r/ in the syllable codas is [x], not [R], according to a friend of mine who teaches phonetics at UFRJ, but also according to some books about Brazilian phonetics ( eg. Cristófaro Silva, Taïs. (1999). Fonética e Fonologia do Português - Roteiro de Estudos e Guia de Exercícios. São Paulo: Ed. Contexto, which is excellent).
When I heard the Carioca dialect first time, I also thought that it was something similar to [R], but then I paid attention and I heard clearly that it was [x]. However, there are many people in Rio who pronounce 'rr' and /r/ in the syllable codas as [h] or [r], but those are immigrants from other parts of Brazil. There are many nordestinos in Rio, for example, who continue pronouncing [h] and who also preserve other phonetic features of their original speech, like opened vowels in unstressed syllables (When you go to the Feira nordestina in Carioca neighborhood of São Cristóvão, you will think that you are not actually in Rio, and not just because of products which are sold, but also because of the speech by which you are surrounded

That demonstrates us the fact that large Brazilian cities, like Rio, São Paulo, Brasília, and others which receive a grate amount of immigrants, linguistically speaking are really melting pots of dialects. I saw many people in Rio who tried to adopt the Carioca accent and adopted only some features, but preserved some of their regional variant. So, there are some grate phonetic diversity that you can hear nowadays in Rio and sometimes it is very difficult to actually describe the contemporary Carioca dialect. My friend from UFRJ told me that they encountered many problems while doing this kind of investigations. Because of all that, some problematic questions occurred in Brazilian (socio)linguistics. What should be considered as Carioca, or Paulistano, or Brasilense original dialect? What are the changes produced by permanent influence of other Brazilian dialects that come to these cities by immigrants? Remember that Cariocas started to pronounce /s/ and /z/ in syllable codas like [ʃ] (before unvoiced consonants) and [ʒ] (before voiced ones) only after the installation of Portuguese Cort in Rio... Migrations of people (interior or exterior) are frequently the most important cause of phonetic changes in some dialect.