[1][2] Unlike most Tibeto-Burman languages, Burmese has a phonological system with two-way aspiration: preaspiration (e.g. မှ hma.

[3] In Burmese, this distinction serves to differentiate causative and non-causative verbs of Sino-Tibetan etymology.

[3] In Old Burmese, postaspiration can be reconstructed to the proto-Burmese language, whereas preaspiration is comparatively newer, having derived from proto-prefixes.

[2] Old Burmese orthography treated the preaspirated consonant as a separate segment, since a special diacritic (ha hto, ှ) had not yet been innovated.

Aside from Pali, the Mon language had significant influence on Old Burmese orthography and vocabulary, as Old Burmese borrowed many lexical items (especially relating to handicrafts, administration, flora and fauna, navigation and architecture), although grammatical influence was minimal.

The most complete set of Old Burmese inscriptions, called She-haung Myanma Kyauksa Mya (ရှေးဟောင်း မြန်မာ ကျောက်စာများ; lit.

"Ancient Stone Inscriptions of Myanmar") was published by Yangon University's Department of Archaeology in five volumes from 1972 to 1987.