It does not, not directly at least, since your melee damage is based on your weapon and your magic attribute. Spell Whisp will however affect your sustained offensive and defensive spells. However, if you were to use Flaming Weapon, Spell Whisp would increase the damage that it would add to your melee attacks.
“The world breaks every one and afterward many are strong at the broken places. But those that will not break it kills. It kills the very good and the very gentle and the very brave impartially.”