  The properties of the pseudoscalar Goldstone bosons in the color-flavor
locked phase at moderate densities are studied within a model of the
Nambu--Jona-Lasinio type. The Goldstone bosons are constructed explicitly by
solving the Bethe-Salpeter equation for quark-quark scattering in random phase
approximation. Main focus of our investigations are (i) the weak decay constant
in the chiral limit, (ii) the masses of the flavored (pseudo-) Goldstone bosons
for non-zero but equal quark masses, (iii) their masses and effective chemical
potentials for non-equal quark masses, and (iv) the onset of kaon condensation.
We compare our results with the predictions of the low-energy effective field
theory. The deviations from results obtained in the weak-coupling limit are
discussed in detail.
