Original sentence: A Proto-Balto-Slavic language is reconstructable by comparative method, descending from Proto-Indo-European by means of well-defined sound laws, and out of which modern Slavic and Baltic languages descended.All major Indo-Europeanists classify Baltic and Slavic languages into a single branch, even though some details of the nature of their relationship remain in dispute in some circles, usually due to political controversies..
Edited sentence: A hypothetical Proto-Balto-Slavic language is also reconstructable, descending from Proto-Indo-European by means of well-defined sound laws, and out of which modern Slavic and Baltic languages descended.However, there is an ongoing debate on the nature of that relationship.Some claim they were genetically related, and others explain similarities by prolonged language contact