  Understanding how molecules engage in collective motions in a liquid where a
network of bonds exists has both fundamental and applied relevance. On the one
hand, it can elucidate the ``ordering" role of long-range correlations in an
otherwise strongly dissipative system; on the other hand, it can inspire new
avenues to control such order to implement sound manipulation. Water represents
an ideal investigation case to unfold these general aspects and, across the
decades, it has been the focus of thorough scrutiny. Despite this investigative
effort, the spectrum of terahertz density fluctuations of water largely remains
a puzzle for Condensed Matter physicists. To unravel it, we compare previous
scattering measurements of water spectra with new ones on ice. Thanks to the
unique asset of Bayesian inference, we draw a more detailed portrayal of the
phonon response of ice. The comparison with the one of liquid water challenges
the current understanding of density fluctuations in water, or more in general,
of any networked liquid.
