fluency [fluencies](quality of smoothness of flow) noun [UK: ˈfluːən.si] [US: ˈfluːən.si]Fluency boils down to one thing: practice. = La fluidez se reduce a una sola cosa: la práctica.
fluidity [fluidities](the state of being fluid rather than viscous) noun [UK: fluː.ˈɪ.dɪ.ti] [US: fluː.ˈɪ.də.ti]