Along with the innovations, which, however, are a continuation of long-existing structure of languages and seamlessly fit into their structure, in Indo-European languages, typological retained basis, which gives the language a so-called harmonious balance. On Today there is an assumption that the Baltic languages in their current state is the closest to the original version of the foundation of Indo-European languages. Scientists have noticed this fact about recently. The reason for this was a general interest in other Indo-European languages and is based on them provide a picture of its parent language. Nowadays there is a new assumption that the Baltic Languages are a kind of 'balance' of Indo-European type. And early in the study of Baltic languages, and today there is a fairly definite point of view that is closest to them languages of the Slavic language group, and then – the German language group. Previously, support the hypothesis of the existence of an intermediate variant of Proto – Slavic-Baltic-German. A.
Leskin conducted research in this area and demonstrated that similar of This trio are the only Slavic and Baltic groups. In the early 20 century in the study of ancient languages of the northern part of the Balkan Peninsula, in particular, Thracian, Illyrian, and only in our time of their continue – the Albanian language, was seen in the proximity of their Balkan languages group. So, on the basis of these data we can describe the distribution area of the Baltic languages in ancient times. From the south, neighboring Baltic tribes were the Thracians and Illyrians in the west – the Germanic tribes from the east – the Slavs, and in the south-east, probably was the border with Iranian tribes.