Kingsley put up a privacy charm so the Weasleys didn't hear Angie's story. Then he set up quill and parchment.
His voice was very neutral and his enunciation was very clear as he spoke for the quill. "This is the witness statement of Angelina Johnson, taken Wednesday, 11 June, 2008, in the matter of the death of Ronald Bilius Weasley. Miss Johnson, please tell me for the record what happened this morning."
The quill scratched along the parchment as he spoke.