Like phosphine itself, but easier, organophosphines undergo protonation.  The reaction is reversible.  Whereas organophosphines are oxygen-sensitive, the protonated derivatives are not.
Primary and secondary derivatives, they can be deprotonated by strong bases to give organophosphide derivatives.  Thus diphenylphosphine reacts with organolithium reagent to give lithium diphenylphosphide:
:HPPh + RLi → LiPPh + RH