It's a personal pronoun that is used in some parts of the Spanish-speaking world instead of 'tú.' It's most commonly associated with Argentinian Spanish, although it's used in some other Latin American countries too. http://study-spanish-language.com/grammar/conjugating-vos/ 'Vos sos' means the same as 'tú eres.'

En Argentina usamos "vos sos" en lugar de "Tú eres" :-)

Hola Lana , es igual a "tu eres" para referirte a una persona. Saludos

Hi Lana, "vos" is similar to "tú", or "you" in English. Now, "sos" it means: "eres", or "are" in English. "You are" = "vos sos". Saludos.

Es como decir " tu" pero de una manera mas con confiansa en ingles seria como you