  Several experimental and theoretical studies in cobaltates suggest the
proximity of the system to charge ordering (CO). We show, qualitatively, in the
frame of a $t-V$ model coupled to phonons that optical phonon modes at the $K$
and $M$ points of the Brillouin zone, which involves only $O$-ions displacement
around a $Co$-ion, are good candidates to display anomalies due to the CO
proximity. If by increasing of $H_2O$ content the system is pushed closer to
CO, the mentioned phonon modes should show softening and broadening.
