As a regular NewsHour watcher, I find it painful to hear Jim Lehrer pronounce Myanmar as ME-and-Mar, for two reasons.The BBC has also weighed in on the topic, favoring the alternative Burma, but its pronunciation guide for those who insist on using Myanmar lists several possibilities—MYAN-mar, my-uhn-MAR, MEE-and-mar, and mi-AN-mar—but recommends myan-MAR (all without pronouncing the final r).
(1) One is the same reason English speakers insist on pronouncing Kyoto in three syllables. They can pronounce kyu in one syllable (as in 'cue ball'), but not kyo. I'm sure Jim can pronounce myu in one syllable, as in 'musing', but can't get mya out in one syllable.
(2) But I wouldn't bother to write you about it if I hadn't heard Jim offer a lame bit of newsroom CW to explain why he insists on using the name he can't pronounce rather than the name he can pronounce. Etymologically, Myanmar and Burma are the same word, just pronounced differently. One is formal and literary, the other more common and colloquial. Here's what a reputable academic specialist says on the matter: "Myanmar/Burma," by Bertil Lintner, in Ethnicity in Asia, ed. by Colin Mackerras (RoutledgeCurzon, 2003), p. 174: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.If an academic source is too arcane, then perhaps Jim will listen to what a fellow journalist, James Fallows, has to say. He, too, insists on saying Burma not Myanmar [but for political reasons].
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.
For more discussion, visit Language Hat.
UPDATE: I'm way out of my depth on the issue of Burmese orthography, but from what I understand, written Burmese and spoken Burmese are in a diglossic relationship perhaps akin to that between Classical Arabic and the rich diversity of contemporary colloquial Arabic, or between Classical Chinese and modern spoken Chinese languages and dialects. Written Chinese underwent drastic reforms during the early 20th century to reflect modern spoken Mandarin, but Burmese still awaits such orthographic reforms. So people may write Burmese as it was spoken 1000 years ago (e.g., Mran-ma) but pronounce the same words the way they have turned out after 1000 years of sound change (e.g., Bam-ma), even writing millennium-old grammatical elements that are now archaic or obsolete in the spoken language. It would be as if all English speakers shared no writing system except a Runic version of Anglo-Saxon.