Combining Diaeresis Below

It adds audible breath to the voiced sound before it. In IPA, a̤ applies this quality to the vowel a; w̤ applies it to the consonant w.

The IPA began in 1886 as a language-teaching project using consistent sound notation. A 1949 chart still wrote breathy vowels as eh and ah; the TIPA manual traces the subscript-umlaut form to the 1979 IPA chart and later charts. TIPA is a LaTeX package for typesetting phonetic text.

Foochow Romanized is a Latin-letter spelling system for Foochow, a variety of Chinese. A 1929 Foochow dictionary prints vowels such as a̤, e̤, and o̤; these spellings follow that system, not IPA.

How do I type diaeresis below?

Put a base letter first, then add the combining mark. Alone, it has no base to modify and may look detached; a̤ shows the order.

Praat’s phonetic editor accepts o\:v for o̤. In the TIPA package for LaTeX typesetting, \textsubumlaut{e} marks e.

In IPA, a lower mark may be displaced around a descender or crowded stack for legibility. Its visible position can vary; above and below still mark different things.