One of undoubtedly Croatian linguistic characteristics in Bosnia is a very widespread use of the ikavian dialect (an amazing literature has been written in the ikavian version of the Croatian language, since the time of Marko Marulic in the 15th century, and also earlier by Glagolitic scribes). Even today many Croats in Istria, Dalmatia, Gorski Kotar, Slavonia, Baranja use it, as well as the Croats in Austria (Gradisce area), Hungary and Yugoslavia (Srijem, Backa). Many traces of its use can be heard also in Bosnia, both among the Croats and Muslims, despite intensive serbization of the language in the period of 1918-1991.
The reader may be surprised to know that there are even traces of runic script on the territory of BiH, like the one from the village of Breza in central Bosnia, dating from 5-6th centuries.
Much more information regarding ethnic and religious history of the Croats in Bosnia, Slavonia and Srijem, and their migrations until the 17th century, can be found in an important monograph [Zivkovic].
Besides the ikavian dialect, the Croats also use two more dialects:
To make out the difference, see how `milk’ is written in these three dialects: MLIKO, MLIJEKO, MLEKO, or `grandfather’: DID, DJED, DED. Another classification of dialects can be made according to how “what” is written (= ca, kaj, sto):
The Croats use all these three dialects. Cakavian exists only among the Croats and is spoken mostly along the Croatian coast and on the islands. Today kajakvian is used to a much lesser extent. Stokavian is the official dialect which is the most widespread. Serbian, Bulgarian and Russian languages are also stokavian. In Croatia one can encounter each of nine possible combinations of speeches: ikavian-cakavian, ikavian-stokavian, ikavian-kajkavian, ijekavian-cakavian, ijekavian-stokavian (being the most widespread), ijekavian-kajkavian etc. Ekavian-stokavian dialect is typical for the Serbs.
The ikavian dialect is spoken also in Slovakia, Ukraine and Bielorussia, which is a consequence of the common history and very probably of the common roots with the Croats in the early Middle Ages. Croats are ethnically also very close to the Czech and Polish people.