umlaute

It is clear that in all these umlaute the new vowel is exactly intermediate between the original vowel of the root and the modifying one of the termination : if the new vowel became identical with its modifier, the result would be not an umlaut but a complete assimilation.

The umlaute, or sounds of periphasis (ä, ö, ü), exist in the Catawba alphabet, e. g., in ómä, himself; túhö, small; dürûbi, iron; but they are not in frequent use.

Other than those of umlaute […]