Accents in Latin

In modern books, Latin is printed without accents. But in early printed books, up to about the middle of the 19th century, Latin could be printed with occasional circumflex, grave or acute accents. They were never obligatory, and many books use them inconsistently.

Circumflex accent

The circumflex accent is used to mark a long vowel:

(a) when a word has two grammatical forms distinguished only by a vowel short in one and long in the other. E.g.

puella nominative "girl", puellâ ablative "by a girl"; cantus nominative "song", cantûs genitive "of a song"; una "one", unâ (also unà) "together".

(b) when a long vowel results from a contraction. E.g.

putârunt for putaverunt; dî for dii; petit present tense, petît perfect tense, for petivit; deum accusative singular, deûm genitive plural (as if a contraction of deorum—it isn't really).

Grave accent

The grave accent (or more rarely the acute) is used:

(a) when a word can have two meanings or represent two different grammatical forms, to mark the one which is less common or felt to be somehow secondary. E.g.

a interjection "O", à preposition "by"; quam feminine accusative singular relative pronoun, quàm "than"; una "one", unà (also unâ) "together"; secundum regem "the second king", secundùm regem "according to the king".

(b) to mark adverbs. E.g.

ità "so"; constantèr "constantly"; vero ablative adjective "true", verò adverb "indeed".

There's a good deal of overlap between (a) and (b); often they can't be clearly distinguished.

Acute accent

The acute accent is occasionally used in place of the grave. The acute can also be used to mark the suffixes -que "and", -ve or -ue "or"; the accent may fall on the suffix itself, immmediately before the suffix, or on the syllable preceding the suffix: aurumq́ue, aurum´que or aurúmque.

Other unfamiliar marks

Most of the marks listed in the Latin abbreviations in blackletter page are not restricted to blackletter, and can be found in many Latin texts of the 16th and 17th centuries.