[MSL]

카톡

  Obviously, it's Korean ("카톡"). Its full name is "카카오톡". In English it's "KakaoTalk" (or just "KaTalk"). In Russian and Bulgarian, I think, it should be "Какао ток" (not "Какао Толк"!) or "Ка Ток".
 More about it (Kakao Talk) in Wikipedia: https://en.wikipedia.org/wiki/KakaoTalk.