even though many other asian languages use tonal spelling, like hmong, they all represent tones by using the same letter each time the tone is used. in hmong, for example, "-b is always" a high tone, "-s" is always a low tone, "-j" is always high-falling tone. in gr, however, each syllable final has its own spelling rules, and many exceptions exist within these rules. for example, first tone words with the final "-a" as in "bā" is written with just one vowel like "ba", except when the syllable begins with an "l-, m-," or "n-", which then must be written as "lha, mha," and "nha" in that order. this is only one of its many rules and exceptions.