Combining Open Mark Below

It marks vowel quality, usually opening or lowering.

After e, i, o, or u, it indicates a more open or lowered vowel; after a, it can indicate a vowel articulated farther back. The double form ᪸ intensifies the opening.

Teuthonista is a system for recording regional speech, built for dialectology—the study of local ways of speaking. It has roots in the nineteenth century. Philipp Lenz presented a system in 1900; the journal Teuthonista presented the named tradition in 1924/25. A Low German print around 1910 shows e᪷. Related Teuthonista and Böhmer-Ascoli work was used to document dialects in Germany, Switzerland, France, and Italy.

Is ᪷ an ogonek or an IPA mark?

Neither: it is its own Teuthonista mark. Unicode's encoding proposal links it to the left half ring below used in the International Phonetic Alphabet (IPA), ◌̜, but treats them as separate characters: dialect sources distinguish their forms, and their transcription values do not always match. Some fonts also make ᪷ look like an ogonek, a hook-shaped mark used below letters. Read the surrounding notation to identify which mark is intended.