Proto-Balto-Slavic language in the context of "Hirt's law"

The Slavic languages, also known as the Slavonic languages, are Indo-European languages spoken primarily by the Slavic peoples and their descendants. They are thought to descend from a proto-language called Proto-Slavic, spoken during the Early Middle Ages, which in turn is thought to have descended from the earlier Proto-Balto-Slavic language, linking the Slavic languages to the Baltic languages in a Balto-Slavic group within the Indo-European family.

The current geographical distribution of natively spoken Slavic languages includes the Balkans, Central and Eastern Europe, and all the way from Western Siberia to the Russian Far East. Furthermore, the diasporas of many Slavic peoples have established isolated minorities of speakers of their languages all over the world. The number of speakers of all Slavic languages together was estimated to be 315 million at the turn of the twenty-first century. It is the largest and most diverse ethno-linguistic group in Europe.

The Balto-Slavic languages form a branch of the Indo-European family of languages, traditionally comprising the Baltic and Slavic languages. Baltic and Slavic languages share several linguistic traits not found in any other Indo-European branch, which points to a period of common development and origin.

A Proto-Balto-Slavic language is reconstructable by the comparative method, descending from Proto-Indo-European by means of well-defined sound laws, and from which modern Slavic and Baltic languages descended. One particularly innovative dialect separated from the Balto-Slavic dialect continuum and became ancestral to the Proto-Slavic language, from which all Slavic languages descended.

There are many widely varying names of Germany in different languages, more so than for any other European nation. For example:

• the German language endonym is Deutschland, from the Old High German diutisc, meaning "of the people";
• the French exonym is Allemagne, from the name of the Alamanni tribe;
• in Italian it is Germania, from the Latin Germania, although the German people are called tedeschi, which is cognate with German Deutsch;
• in Polish it is Niemcy, from the Proto-Slavic *němьcь, meaning speechless, since German is not mutually intelligible with Slavic languages;
• in Finnish it is Saksa, from the name of the Saxon tribe;
• in Lithuanian it is Vokietija, of unclear origin, but possibly from Proto-Balto-Slavic *vākyā-, meaning “those who speak loud, shout (unintelligibly)”.

Often language lags behind the changing society and names tend to retain references to first encounters: the Finnish first and foremost met the Saxons while the French faced the Alamanni. Comparable tendencies appear elsewhere, e.g. in names for Russia.

The Slavic second palatalization is a Proto-Slavic sound change that manifested as a regressive palatalization of inherited Balto-Slavic velar consonants that occurred after the first and before the third Slavic palatalizations.

The Proto-Slavic language, the hypothetical ancestor of the modern-day Slavic languages, developed from the ancestral Proto-Balto-Slavic language (c. 1500 BC), which is the parent language of the Balto-Slavic languages (both the Slavic and Baltic languages, e.g. Latvian and Lithuanian). The first 2,000 years or so consist of the pre-Slavic era, a long period during which none of the later dialectal differences between Slavic languages had yet emerged. The last stage in which the language remained without internal differences that later characterize different Slavic languages can be dated around AD 500 and is sometimes termed Proto-Slavic proper or Early Common Slavic. Following this is the Common Slavic period (c. 500–1000), during which the first dialectal differences appeared but the entire Slavic-speaking area continued to function as a single language, with sound changes tending to spread throughout the entire area. By around 1000, the area had broken up into separate East Slavic, West Slavic and South Slavic languages, and in the following centuries it broke up further into the various modern Slavic languages of which the following are extant: Belarusian, Russian, Rusyn and Ukrainian in the East; Czech, Slovak, Polish, Kashubian and the Sorbian languages in the West, and Bulgarian, Macedonian, Serbo-Croatian and Slovenian in the South.

The period from the early centuries AD to the end of the Common Slavic period around 1000 was a time of rapid change, concurrent with the explosive growth of the Slavic-speaking area. By the end of this period, most of the features of the modern Slavic languages had been established. The first historical documentation of the Slavic languages is found in isolated names and words in Greek documents starting in the 6th century, when Slavic-speaking tribes first came in contact with the Greek-speaking Byzantine Empire. The first continuous texts date from the late 9th century and were written in Old Church Slavonic—based on the Slavic dialect used in the region of Thessaloniki in Greek Macedonia—as part of the Christianization of the Slavs by Saints Cyril and Methodius and their followers. Because these texts were written during the Common Slavic period, the language they document is close to the ancestral Proto-Slavic language and is still presenting enough unity, therefore it is critically important to the linguistic reconstruction of Slavic-language history.