In 1989, Burma's military government changed the name of the country to Myanmar. The reason, it said, was that the British colonial power had named it 'Burma' after the main ethnic group in the country, the Burmese, who inhabit the central plains. 'Myanmar', it was argued, included the Burmese and all other 'ethnic races', including the Shan, the Karen, the Mon, the Kachin and more than 100 other nationalities. This is, however, historically and linguistically highly dubious. The once-British colony has always been called Burma in English and bama or myanma in Burmese. [The Japanese designation biruma would thus appear to have come from the English spelling.]SOURCE: "Myanmar/Burma," by Bertil Lintner, in Ethnicity in Asia, ed. by Colin Mackerras (RoutledgeCurzon, 2003), p. 174
The best explanation of the difference between bama and myanma is to be found in the Hobson-Jobson Dictionary, which remains a very useful source of information. 'The name [Burma] is taken from Mran-ma, the national name of the Burmese people, which they themselves generally pronounce Bam-ma, unless speaking formally and emphatically.'
Both names have been used interchangeably throughout history, with Burma being more colloquial and Myanmar more formal. Burma and Myanmar (and Burmese and Myanmar) mean exactly the same thing, and it is hard to argue that the term 'Myanmar' would include any more people within the present union than the name 'Burma'.
There is no term in the language that includes both the Burmans and the minority peoples, since no country with the borders of present-day Burma existed before the arrival of the British in the nineteenth century. Burma, with its present boundaries, is a colonial creation rife with internal contractions and divisions.