Some say she found her talent quite by accident. Others believe she dragged it out from the warped heart she may or may not have possessed; that it came to her and she twisted it into coils of tightly knotted screams.
Bellatrix knew not the truth of either matter; it was buried under her decades of lies.
She knew only the screams that it drew. Ones so sharp and jagged that they quivered in the air, lightning flashing across grim sky. Some screams rough and low, keening.
Bella knew every pitch, every corner of the eerie sounds. They were hers, just like Narcissa's cold beauty belonged to her icy eyes, or like Sirius' careless pride showed in his every movement.
Everyone breaks; she knew that. She had watched Cissy cry over her only son. Seen Sirius pleading for relief, desperate in his pain.
But Bella carved the screams from writhing bodies, claimed the ones who fell under her; claimed their howls of agony for her own. And she lived from them.
The wretched pleading of a single scream forced from ones so proud; that was her music. Melodies of wavering voices; it was what Bella played. And those high, soft cries took away her own.
So some might say the screams became from her twisted heart, and Bella deigns to refuse it, but the truth resides in the shadows of those lies.
That heart of hers was twisted by the screams.