In the Romance languages, metaphony was an early vowel mutation process that operated in all Romance languages to varying degrees, raising (or sometimes diphthongizing) certain stressed vowels in words with a final /i/ or /u/ or a directly following /j/. This is conceptually similar to the umlaut process so characteristic of the Germanic languages. Metaphony is most extensive in the Italo-Romance languages, and applies to nearly all languages of Italy. However, it is absent from Tuscan, and hence from standard Italian.