The Speed Guide for Combat (global, weapons, talents)

[Tigerle]

Hits Per Turn = Global_Speed / ((1/Weapon Speed) x (1/Attack Speed)) <--- Great formular in the wiki . I have simplified it to
Hits Per Turn = Global_Speed x Weapon_Speed x Attack_Speed

[antimagicogre]

If your Hits per Turn(HpT) was S, then the TpH is 1/S.
When you attack, you spend a 1/S turn, acquiring a (1 - 1/S) turn.
And sometime in the future, you will get an additional TURN.