From a fundamental point of view, the family of compounds known as phosphorus oxoacids are among the most intriguing proton conducting systems. Neat liquid phosphoric acid (H3PO4) has the highest intrinsic proton conductivity of any known substance. Systems containing phosphates play a central role in the structure and function of biological systems and are attracting increasing interest as electrolytes for emerging fuel cell applications. This is the only known system where the effects of variation in number of potential proton donors and acceptor sites (H-bond network topology) in the order phosphoric (H3PO4), phosphonic (H3PO3) and phosphinic acid (H3PO2) on the proton transport properties, can be addressed in systematic way.With QENS we study the global proton dynamics of the hydrogen network on a local spatial scale and we expect that, especially in combination with MD simulations, we can provide important insights into the relationship between proton transport and other properties (topology, energetics, dynamics) of the hydrogen bond network.