Combining Left Half Ring Below

It tells you to round your lips less for the sound beneath it. The IPA writes speech sounds; u̜ keeps the base vowel u and adds weaker rounding. “Less” need not mean none: this mark alone does not turn u into ɯ, the IPA symbol for an unrounded vowel.

The IPA began as a practical aid for teaching pronunciation. Its first published alphabet appeared in 1888. An archived 1928 chart labels this the “open vowel” mark; later charts call it “less rounded,” showing how the notation's label changed.

The 1989 Kiel Convention, where the IPA was revised, was a major change point, not this mark's origin. Its use in phonetic notation predates digital encoding.

How do I attach it to a sound symbol?

Enter the sound symbol first, then this mark. In a sequence such as u̜, the mark applies to the preceding base. Fonts position it beneath that base, so its exact placement can vary by letter and typeface.

The old label has a documented history

A 2014 Unicode proposal connects the earlier IPA “open vowel” mark to an open or lenis mark in Teuthonista, a notation used to write German regional speech. “Lenis” means relatively weakly articulated. This is a historical notation link, not a guess from similar shapes.