The inscriptions are Slavic:
Ikavian is still spoken by the Croats in Dalmatia, Bosnia, Istria, Slavonia and Vojvodina and partly by the Bosnian muslims in Central and western Bosnia.
The stecci confirm what we all already knew about the strategic role of the Vlachs within the Slavic states ,they had complete military and commercial responsabilities.At that time,they spoke both Slavic and Romanian,with the traditional form of organization ,katun,preserved,while many toponims and even original names have also survived until the modern period.
These Slavic states have offered lots of opportunities for them,so that's why they choose Slavic,because they were some of the representatives of the Serbian,Croatian,Bosnian kings and nobles ,it legitimized them.
Many stecci have bows and swords carved,while the right hand raised means vassality.Lots of Vlachs were very wealthy,they traded with Venice,that's why the most important site seems to be Radimlja.The Venetians didn't liked them that much ,because they oftenly caused unrest in their cities,some laws chased them away after trading.
Things were different in the Bulgarian Empire,this was a very large state,conquered by the Greeks,we definitely had an extended autonomy.
Not to mention that I have personally met them,very nice people,by the way.
Still,they have that strong Byzantine-Orthodox manners,which made me think that Ochrid was quite far from us,because our elders had clearly seen Orthodoxy differently,a matter of pride,status,more individualistic,probably that's why the Patriarch from Constantinople used to call the Early Wallachian Orthodoxy heretic.
Gentlemen,there is a Romanian Orthodoxy,in Curtea de Arges ,you could still hear' Domne miserere' in the 16th,17th c.