Bengali AU Length Mark

It completes the two-part Bengali AU vowel sign from the right.

The AU matra, also called au-kar, has two parts in ordinary Bangla. In text order, the consonant comes first, followed by left-side ে and then ৗ; Bengali shaping places the parts on both sides of the consonant. ক + ে + ৗ becomes কৌ.

The Bengali script developed gradually from eastern Brahmi, an early regional branch of the Brahmi writing tradition. The Mahasthan inscription, an early written record from Bengal, dates to around 300 BCE; that is regional context, not the date of this mark. Bengali and Devanagari are historically related scripts, each with its own signs.

Why does ৗ sometimes look wrong?

The two-piece vowel sign needs Bengali-aware shaping.

Unicode encodes ৗ separately because the AU matra was represented as two visible pieces around a consonant, preserving compatibility with existing text. The complete sign ৌ has a one-character form and a canonically equivalent two-part spelling, ৌ; both represent the same sign, but the two-part form needs Bengali-aware positioning.

If the pieces drift, the shaping engine has failed to position the decomposed sequence; the vowel has not changed. In Bengali-script Kokborok, অৗ can mark an initial vowel glide roughly from “a” toward “u.” Ordinary Bangla does not use ৗ independently that way.