There are three such registers in Burmese, which have traditionally been considered three of the four 'tones'. (The fourth is not a tone at all, but a closed syllable, called "entering tone" in translations of Chinese phonetics). Jones (1986) views the differences as
|High||Breathy voice||long||high; falling when final||[lá̤ː] ~ [lâ̤ː]||'mule'|
|Checked||Final glottal stop||short||high||[lăʔ]||'fresh'|
Khmer is sometimes considered to be a register language. It's also been called a "restructured register language" because both its pitch and phonation can be considered allophonic: If they are ignored, the phonemic distinctions they carry remain as a difference in diphthongs and vowel length.