In modern German, umlaut as a marker of the plural of nouns is a regular feature of the language, and although umlaut itself is no longer a productive force in German, new plurals of this type can be created by analogy. Likewise, umlaut marks the comparative of many adjectives and other kinds of derived forms. Because of the grammatical importance of such pairs, the German umlaut diacritic was developed, making the phenomenon very visible. The result in German is that the vowels written as , , and become , , and , and the diphthong becomes : "Mann" "man" vs. "Männer" "men", "Fuß" "foot" vs. "Füße" "feet", "Maus" "mouse" vs. "Mäuse" "mice".