Tibeto-Burman (TB) languages, including the Ngwi (Loloish, Yi Branch) languages have two-syllable lexical time ordinals (yesterday, today, tomorrow; last year, this year, next year and so on) for up to a maximum of nine days and years in the past and in the future. These are usually compounds with one bound lexical ordinal element followed by one analyzable element meaning ‘day' or ‘year'; some languages also allow some or all of ‘morning', ‘evening' and ‘night' to occur in the second slot, especially for the time ordinals closest to the present. For time ordinals closest to the present, the forms are often less analyzable; this is particularly true for ‘tomorrow' and ‘next year'.

These time ordinals may contain fossilized cognate lexical material otherwise absent from a language or subgroup of TB, but otherwise widespread across TB. For example, Lisu has [ni35] in year ordinals, cognate with Proto-Eastern TB *s-nik; otherwise, Lisu has [kho21] for ‘year' as elsewhere in Ngwi (Loloish) languages. In some subgroups of TB, some of the bound time ordinal forms resemble numerals, but are not identical in form; this presumably reflects their compound origins. In other subgroups, the bound forms do not resemble numerals.

Phonological sound correspondences seen in nominal and verbal stems are not followed as regularly in the bound elements of these time ordinal forms. This may be due to sandhi effects within these two-syllable compounds, and to paradigmatic effects from adjacent items in the day or year ordinal paradigms.

Data from Ngwi (Loloish, Yi Branch) languages of Sichuan is presented, derived from two clusters: Northern Ngwi Nuosu, and its subvarieties including Yinuo, Lindimu, Suondi and Adur as spoken in various parts of Liangshan; and Central Ngwi Lipo and Lisu as spoken in Panzhihua and southwestern Liangshan.