  We consider QCD at a nonzero chemical potential for strangeness. At a
critical value of the chemical potential equal to the kaon mass, kaon
condensation occurs through a continuous phase transition. We show that, when
the isospin symmetry is exact in the Lagrangian, a Goldstone boson with a
dispersion relation $E \sim p^2$ appears in the kaon condensed phase. At the
same time, the number of the Goldstone bosons is less than the number of broken
generators. Both phenomena are familiar in non-relativistic systems. We
interpret our results in terms of a Goldstone boson counting rule found
previously by Nielsen and Chadha. We also formulate a criterion sufficient for
the equality between the number of Goldstone bosons and the number of broken
generators.
