A low frequency light scattering study of the (AgI)x(AgPO3)1-x superionic glasses is presented for different AgI content (0 < x < 0.55) and in the temperature range 18-330 K. It is possible to investigate the full spectral range of interest (0.2-250 cm-1 frequency shift) analyzing Brillouin and Raman scattering by means of the same spectrometer. The Raman spectra consist of long tails of a quasi-elastic contribution superimposed on a one-phonon, disorder induced light scattering. Thanks to their differing temperature behaviour, it has been possible to separate these two contributions and to identify the spectral shape of the quasi-elastic scattering. The quasi-elastic contribution has a Lorentzian-like shape, the intensity of which increases almost linearly with increasing AgI concentration and, for a given AgI content, quadratically increases with temperature. The spectral widths are constant in temperature and decrease with increasing AgI content. From the good quality experimental data (which are the main result of the present paper), the quasi-elastic scattering is not related to the high ionic mobility of silver ions. Even if it is not possible to give a definitive interpretation of the low frequency light scattering spectrum, it seems reasonable to assign it to some type of structural relaxation whose characteristic time increases with increasing AgI content.14341700274281