Khmer

Khmer has one of the largest letter inventories of any script in daily use, and one of the oldest pedigrees in Southeast Asia — the oldest dated inscription is from 611 CE, placing it among the earliest written languages of the region. It descends, by way of the Pallava script of southern India, from the Brahmi family; the site records its heirs in the Brahmi Wing.

Two features stand out. First, its consonants come in two series (sometimes called registers): the same vowel sign is pronounced differently depending on whether the consonant belongs to the a-series or the o-series, so the consonant chooses the vowel's colour. Second, when consonants cluster with no vowel between them, the second consonant is written as a subscript — a smaller form tucked beneath the first (the "coeng"), so syllables build downward as well as across.

Consonants do not queue; they stack.

Cambodian text, like Thai, runs without spaces between words — a reader parses the syllable clusters directly. See the descent diagram in the Hall of Lineages, where Khmer's strong influence on the Thai and Lao scripts is recorded alongside its own line of descent.

Two mechanisms shape a Khmer syllable. First, every consonant belongs to one of two series — the a-series or the o-series — and the series colours the vowel: a single vowel sign is read one way after an a-series consonant and another way after an o-series consonant. Second, when two consonants meet with no vowel between them, the second is written not beside the first but beneath it, as a subscript form called the coeng. Syllables therefore build downward as well as across.