Brazilian Portuguese (Portuguese: português brasileiro, português do Brasil; pt-BR) is the variety of the Portuguese language used in Brazil. It is written and spoken by virtually all of the 190 million inhabitants of Brazil and by a few million Brazilian emigrants, mainly in the United States, Paraguay, Japan, Portugal, and Argentina.
Some authors compare the differences between Brazilian Portuguese and European Portuguese to those found between American and British English. Others debate whether the two spoken varieties are still "the same language" or whether Brazilian Portuguese can be classified as a "different language". The formal written language in Portugal and Brazil differs much less than the spoken varieties, and that difference has been further reduced by agreements on spelling reform in the 1940s, the early 1970s, and 1990.
In 1990 an agreement between Brazil and the other Lusophone countries was established to reduce the differences among their respective spelling conventions. The Portuguese Language Orthographic Agreement of 1990 (Portuguese: Acordo Ortográfico da Língua Portuguesa de 1990) is an international treaty whose purpose was meant to create a unified orthography for the Portuguese language, to be used by all the countries that have Portuguese as their official language. However, the agreement has not yet been ratified by all, due to a variety of specific problems.