The modern Croatian standard language is a continuous outgrowth of more than nine hundred years of literature written in a mixture of Croatian Church Slavonic and the vernacular language. If the subject is narrowed out, Croatian Church Slavonic had been abandoned by the mid-1400s, and Croatian "purely" vernacular literature has existed for more than five centuries — a story of remarkable linguistic continuity with only a few shock points.
The beginning of the Croatian written language can be traced to the 9th century, when Old Church Slavonic was adopted as the language of the liturgy. This language was gradually adapted to non-liturgical purposes and became known as the Croatian version of Old Slavonic. The two variants of the language, liturgical and non-liturgical, continued to be a part of the Glagolitic service as late as the mid-9th century.
Although the first purely vernacular texts in a Croatian distinctly different from Church Slavonic date back to the 13th century, it was in the 14th and 15th centuries that the modern Croatian language emerged (recorded in texts as Vatican Croatian prayer book from 1400.) in the form (morphology, phonology and syntax) that only slightly differs from contemporary Croatian standard language.
Croatian, like most other Slavic languages has a rich system of inflection. Pronouns, nouns, adjectives and some numerals decline (change the word ending to reflect case, i.e. grammatical category and function), while verbs conjugate for person and tense.
Nouns have three grammatical genders (masculine, feminine and neutral) that correspond to a certain extent with the word ending, so that most nouns ending in -a are feminine, -o and -e neutral and the rest mostly masculine with a small but important class of feminines. Grammatical gender of a noun affects the morphology of other parts of speech (adjectives, pronouns and verbs) attached to it.
Verbs are divided into two broad classes according to their aspect, which can be either perfective (signifying a completed action) or imperfective (action is incomplete or repetitive). There are seven tenses, four of which (present, perfect, future I and II) are used in contemporary standard Croatian, with the other three (aorist, imperfect and plusquamperfect) considered stylistically marked and archaic.