Here’s a translation of the lyrics:
“Warning”
Listen, I’ll tell you my secret:
never leave me alone
when someone is playing music.

A pair of completely normal eyes
might seem to me
deep and soft.

It might seem to me
that I’m drowning in the sounds,
and I’ll shake the hands
of everyone around.

It might seem to me
easy and beautiful
to love someone shortly,
for only one day.

Or I could tell someone
in that hour my marvelously
luminous and dear secret –
how much I love you.

Oh, don’t ever leave me alone
When someone is playing music.

It will seem to me that somewhere in the forest
all my tears are again flowing
through the wild growths of some fountain.

It will seem to me that a black butterfly
traces out, with its wing, upon heavy water,
what someone once did not dare to tell me.

It will seem to me that somewhere through the darkness
Someone is singing, and with a bitter flower,
Is touching the incurable wound of my heart.

Oh, don’t ever leave me alone
When someone is playing music.

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