Strong acid
Weak acid

But adding base causes the equilibrium to shift, according to LeChâtelier's Principle, and as H⁺ is consumed, more of the weak acid breaks up to replace the amount that has reacted. This behavior is rapid enough that there is no real difference in the stoichiometric end result. But getting there is somewhat different.

The tendency of weak acid anions (like CH₃COO^-) or weak base cations (like NH₄⁺) to recombine with hydrogen or hydroxide ions (or exchange protons with other aqueous species) sets the stage for other interesting aqueous behavior including some of the differences in the titration curves we have examined. Stay tuned....