  Pseudo-Goldstone modes appear in many physical systems and display robust
universal features. First, their mass $m$ obeys the so-called
Gell-Mann-Oakes-Renner (GMOR) relation $f^2\,m^2=H\,\bar{\sigma}$, with $f$ the
Goldstone stiffness, $H$ the explicit breaking scale and $\bar{\sigma}$ the
spontaneous condensate. More recently, it has been shown that their damping
$\Omega$ is constrained to follow the relation $\Omega=m^2 D_\varphi$, where
$D_\varphi$ is the Goldstone diffusivity in the purely spontaneous phase. Pions
are the most paradigmatic example of pseudo-Goldstone modes and they are
related to chiral symmetry breaking in QCD. In this work, we consider a
bottom-up soft-wall AdS-QCD model with broken ${\rm{SU}}(2)_L \times
{\rm{SU}}(2)_R$ symmetry and we study the nature of the associated
pseudo-Goldstone modes -- the pions. In particular, we perform a detailed
investigation of their dispersion relation in presence of dissipation, of the
role of the explicit breaking induced by the quark masses and of the dynamics
near the critical point. Taking advantage of the microscopic information
provided by the holographic model, we give quantitative predictions for all the
coefficients appearing in the effective description. In particular, we estimate
the finite temperature behavior of the kinetic parameter $\mathfrak{r^2}$
defined as the ration between the Goldstone diffusivity $D_\varphi$ and the
pion attenuation constant $D_A$. Interestingly, we observe important deviations
from the value $\mathfrak{r^2}=3/4$ computed in chiral perturbation theory in
the limit of zero temperature.
