Croatian is a language of the western group of South Slavic languages which is used primarily by the Croats. It is one of the standard versions of the Central-South Slavic diasystem. Croatian is based on the Štokavian dialect (with some influence from Čakavian and Kajkavian) and written with the Latin alphabet. 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 we narrow out the subject, Croatian Church Slavonic had been abandoned by the mid-1400s, and Croatian "purely" vernacular literature has been in existence for more than five centuries — a story of remarkable linguistic continuity with only a few shock points.
The division between Croats and Serbs originates in the 11th century, when both groups converted to Christianity. The Serbs aligned themselves with Constantinople and the Eastern Orthodox church and adopted the Cyrillic alphabet though also use the Latin alphabet, while the Croats favoured the Roman Catholic church and the Glagolitic alphabet. The Latin alphabet was gradually adopted by the Croats, though they continued to use Glagolitic for religious writings until the 19th century. After the Turkish conquest of Serbia and Bosnia, Islam spread to parts of Bosnia and the Arabic script was sometimes used.
Today Croatian is written with the Latin alphabet, Serbian is written mainly with the Cyrillic alphabet, though the Latin alphabet is sometimes used, and Bosnian uses both alphabets.
Croatian contains many words of Latin and German origin but many new Croatian words are created by combining and adapting existing ones.