You may not know this - or never stopped to think about it - but two people can pick up the same exact guitar, plug it into the exact same amp, strum the same chord, but achieve different results.
Additionally, a person who has never played an instrument and has zero understanding of music theory can't tell you how to play their favorite song, but chances are they can tell if you're playing it wrong.
These concepts are why music is the universal language. In the first scenario: no two people will ever have identical voices and use identical vocabulary. In the second: even if a person doesn't understand the language you're speaking they...