Aún no tenemos significados para "speak incisively".
1He spoke incisively enough, but shook his head with a smile.
2She spoke incisively and her voice was deep and resonant.
3He spoke incisively and bitterly, and he was obviously excited, but he affected his usual composure.
4Then, as if suddenly making up his mind to hit hard, as a surgeon might decide to use the knife, he spoke incisively: