modifier letter extra-low dotted left-stem tone bar

꜑ marks an extra-low tone in a specialist pitch transcription. Tone letters are small marks written beside a syllable to record pitch. The dot flags a short, weak or “neutral” reading; a left stem marks the surface value after sandhi. Alone, it names no word and no fixed tone.

The linguist Yuen Ren Chao proposed tone letters in 1930: a reference line beside a simplified pitch curve, so Chinese contours could be printed exactly. A 2003 Unicode review describes dotted forms for weak or neutral syllables and left-stem forms for sandhi; ꜑ combines both.

why does the left stem matter?

It writes the surface tone, not the underlying one. Unicode documents a paired notation: right-stem letters write the underlying tone, left-stem letters the tone as it surfaces beside its neighbours — the ꜑ sandhi pattern. Dotted left-stem forms extend that pairing to weak or neutral syllables.

The same Unicode block keeps the older Chinese corner tone letters ꜀–꜇ — marks placed at a syllable's corner to show tone category, tied to the 1830s system of Bridgman and Wells Williams. Relatives, not earlier forms of ꜑.