du spielst = you play/you're playing (informal, addressing one person)
ihr spielt = you play/you're playing (informal, addressing more than one person)
Sie [upper case] spielen = you play/you're playing (formal, addressing one or more people)
sie [lower case] spielen = they play/they're playing
sie [lower case]spielt = she plays/she's playing
How can you hear the upper case spelling when the word is spoken? I'm very confused now - Sie/sie (sounding the same?) means you, they or she??? How can you tell the difference? OK, different conjugation in one case, but that still leaves "you" or "they", sounding the same.