With Portuguese the dominant language in the areas of heavy Brazilian migration and Brazilian currency circulating as legal tender , the area became closely integrated with Brazil .
By the mid-1980s , observers estimated there were between 300,000 and 350,000 Brazilians in the eastern border region .
With Portuguese the dominant language in the areas of heavy Brazilians migration and Brazilians currency circulating as legal tender , the area became closely integrated with Brazilians .
By the mid-1980s , observers estimated there were between 300,000 and 350,000 Brazilians in the eastern border region .