Why do some Uralic languages have voiced and voiceless consonant contrasts?

Some Uralic languages, such as Hungarian and Komi, have developed a contrast between voiced and voiceless consonants—a distinction not present in the early stages of the language family.1

The presence of this voicing contrast in these specific languages is attributed to the influence of neighboring Indo-European and Turkic languages. While some Uralic languages exhibit consonant alternations known as consonant gradation (or lenition), where single stops may weaken or voice between vowels, this process is distinct from the active voicing contrast found in languages like Hungarian.12