common use of diacritics in Romance languages. Vowel quality: the system of marking close-mid vowels with an acute accent, é, and open-mid vowels with a grave accent, è, is widely used (e.g. Catalan, French, Italian). Portuguese, however, uses the circumflex (ê) for the former, and the acute (é), for the latter. Some minority Romance languages use an umlaut (diaeresis mark) in the case of ä, ö, ü to indicate fronted vowel variants, as in German. Centralized vowels () are indicated variously (â in Portuguese, ă/î in Romanian, ë in Piedmontese, etc.). In French, Occitan and Romanian, these accents are used whenever necessary to distinguish the appropriate vowel quality, but in the other languages, they are used only when it is necessary to mark unpredictable stress, or in some cases to distinguish homophones. Vowel length: French uses a circumflex to indicate what had been a long vowel (although nowadays this rather indicates a difference in vowel quality, if it has any effect at all on pronunciation). This same usage is found in some minority languages. Nasality: Portuguese marks nasal vowels with a tilde (ã) when they occur before other written vowels and in some other instances. Palatalization: some historical palatalizations are indicated with the cedilla (ç) in French, Catalan, Occitan and Portuguese. In Spanish and several other world languages influenced by it, the grapheme ñ represents a palatal nasal consonant. Separate pronunciation: when a vowel and another letter that would normally be combined into a digraph with a single sound are exceptionally pronounced apart, this is often indicated with a diaeresis mark on the vowel. This is particularly common in the case of gü /ɡw/ before e or i, because plain gu in this case would be pronounced /ɡ/. This usage occurs in Spanish, French, Catalan and Occitan, and occurred before the 2009 spelling reform in Brazilian Portuguese. French also uses the diaeresis on the second of two adjacent vowels to indicate that both are pronounced separately, as in Noël "Christmas" and haïr "to hate". Stress: the stressed vowel in a polysyllabic word may be indicated with an accent, when it cannot be predicted by rule. In Italian, Portuguese and Catalan, the choice of accent (acute, grave or circumflex) may depend on vowel quality. When no quality needs to be indicated, an acute accent is normally used (ú), but Italian and Romansh use a grave accent (ù). Portuguese puts a diacritic