How do minor syllables occur in Tibeto-Burman words?

In Tibeto-Burman languages, minor syllables typically arise through the process of grammatical specialization, where root morphemes—such as full nouns or verbs—are repurposed to function as grammatical markers. As these words undergo this transition, they often experience a reduction in their phonological shape, frequently through destressing, and may acquire a special tone.1

Additionally, some suffixes in Tibeto-Burman are considered minor syllables because they possess a highly reduced set of vowels and tones. These syllables are characterized by their lack of the full phonological substance found in primary root morphemes. While these features are common in the region, they are not clearly attributable to the Proto-Tibeto-Burman stage itself, as they are also shared by neighboring language families like Austroasiatic and Hmong-Mien.21