In both Ancient and Modern Greek, crasis merges a small word and long word closely connected in meaning. In Ancient Greek, a coronis marks the vowel from crasis. In ancient times, it was an apostrophe placed after the vowel, but it is now written over the vowel τἀμά, and it is identical tosmooth breathing in Unicode. Unlike a coronis, smooth breathing never occurs on a vowel in the middle of a word. The article undergoes crasis with nouns and adjectives that start with a vowel:
τὰ ἐμά → τᾱ̓μά "my "
τὸ ἐναντίον → τοὐναντίον "on the contrary"
τὸ αὐτό → ταὐτό "the same"
τὰ αὐτά → ταὐτά
καί undergoes crasis with the first-person singular pronoun and produces a long vowel:
καὶ ἐγώ → κᾱ̓γώ "and I", "I too"
καὶ ἐμοί → κᾱ̓μοί "and to me"
In modern monotonic orthography, the coronis is not written.
French
In French, the contractions of determiners are often the results of a vocalisation and a crasis:
de le → du, de les → des
à le → au, à les → aux
en les → ès
Portuguese
The most frequently observed crasis today is the contraction of the preposition a with the feminine singular definite articlea, indicated in writing with a grave accent, or the masculine singular definite article o. For example, instead of *Vou a a praia, one says Vou à praia. The contraction turns the clitica into the stressed word à. Meanwhile, a person going to a bank, a supermarket or a marketplace would say Vou ao banco, Vou ao supermercado or Vou à feira, respectively. Crasis also occurs between the preposition a and demonstratives: for instance, when the preposition precedes aquele, aquela, they contract to àquele, àquela. The accent marks a secondary stress in Portuguese. In addition, the crasis à is pronounced lower as than the article or preposition a, as, in the examples in standard European Portuguese, but the qualitative distinction is not made by most speakers in Brazilian Portuguese. Crasis is very important, as it can change the meaning of a sentence:
These rules determine whether the crasis always apply, or whether one may use the contraction à instead of the preposition a : Replace the preposition a by another preposition, as em or para. If, with replacement, the definite article a is still possible, crasis applies:
Pedro viajou à Região Nordeste: with a grave accent because it equivalent to "Pedro traveled 'to the' Northeast Region". Here, para a Região Nordeste could also be used.
O autor dedicou o livro a sua esposa: without a grave accent in Brazilian Portuguese because it is equivalent to "The author dedicated the book 'to' his wife". A consistent use, according to the rules in Brazil would not allow para a sua esposa be used instead. In European Portuguese, nevertheless, rules are different, and it is O autor dedicou o livro à sua esposa, but in English, both sentences have the same meaning.
If the nominal complement is changed, after "a", from a feminine noun to a masculine noun and it is now necessary to use 'ao', crasis applies:
Prestou relevantes serviços à comunidade, He/she paid outstanding services to the community: with a grave accent because if one changes the object to a masculine noun, one now uses "ao".
"Chegarei daqui a uma hora" I will arrive in an hour: without crasis because when the femi one noun is changed to a masculine noun, there is no "ao".
The grave accent is never used before masculine words ; verbs; personal pronouns; numerals, plural nouns without the use of the feminine plural definite article as ; city names that do not use a feminine article; the wordcasa if it has the meaning of one's own home;/the word terra when it has the meaning of soil; and indefinite, personal, relative or demonstrative pronouns or aquela; between identical nouns such as dia a dia "day by day", "everyday", "daily life", gota a gota "dropwise", "drip", and cara a cara "face to face"; and after prepositions. Here are exceptions: É preciso declarar guerra à guerra! É preciso dar mais vida à vida.
Optional crasis
The grave accent is optional in the following cases:
