As with the issue of Macedonian ethnicity, the politicians, linguists and common people from Macedonia and neighbouring countries have opposing views about the existence and distinctiveness of the Macedonian language.
In the ninth century AD, saints Cyril and Methodius introduced Old Church Slavonic, the first Slavic language of literacy. Written with their newly invented Glagolitic script, this language was based largely on the dialect of Slavs spoken in Thessaloniki; this dialect is closest to present day Bulgarian and Macedonian and the official modern Macedonian view, prevalent in books printed in the Republic of Macedonia, is that Macedonian was the first official language of Slavs.
Bulgaria recognized the Macedonian language from 1944 until 1948, the date of the Tito-Stalin split. This date also coincided with the first referenced efforts of Bulgarian linguists to the Serbianisation of the Macedonian language. Although Bulgaria was the first country to recognize the independence of the Republic of Macedonia, it has since refused to recognise the existence of a separate Macedonian nation and a separate Macedonian language. Unlike Bulgaria, Serbia has acknowledged a separate Macedonian and language since the end of the Second World War.
Bulgarian linguists and scientists regard Macedonian as a dialect of the Bulgarian language. Although described as being dialects of Bulgarian prior to the establishment of the standard, the current academic consensus outside Bulgaria is that Macedonian is an autonomous language within the South Slavic dialect continuum.
In most sources in and out of Bulgaria before the Second World War, the southern Slavonic dialect continuum covering the area of today's Republic of Macedonia were referred to as Bulgarian dialects. After WWII, the question about the Macedonian language was forgotten in the name of the Bulgaro-Yugoslavian friendship under the pressure of the Soviet Union
According to the linguistic publication Ethnologue, alternative names include "Macedonian Slavic" and (in Greece) "Slavic". The use of the name Macedonian for the language is considered offensive by Greeks, who assert that the northern Greek ancient Macedonian language is the only "Macedonian language." Greeks object to the use of the "Macedonian" name in reference to the modern Slavic language, calling it "Slavomacedonian" (Macedonian: славомакедонски јазик, Greek: σλαβομακεδονική γλώσσα), a term introduced and accepted by the Slavic-speaking community of northern Greece itself, or "Skopian", which, since the 1990s, are considered pejorative terms by ethnic Macedonians (i.e. people with that national identity). Terms such as Slav Macedonian have also been used. The European Bureau for Lesser-Used Languages is of the opinion that the language spoken by the Slavophone Greeks in Greek Macedonia should in fact be called "Macedonian" and it appropriate recognises it as such.