  We study a mechanism for the amplification of the inflationary scalar
perturbation when the inflaton field action is non-canonical, i.e. the inflaton
kinetic term has a non-standard form. For such a case the speed of sound of the
perturbations generated during inflation is less than one and in general
changes with time. Furthermore in such models, even when the scalar field
potential is negligible, diverse inflationary attractors may exist. The
possible effects of a speed of sound approaching zero during some stage of
inflation may lead to a large amplification for the amplitude of the scalar
spectrum which, on horizon re-entry during the radiation dominated phase, can
collapse and form primordial black holes (PBH) of a mass $M_{\rm BH}\sim
10^{-15}M_{\odot}$ which may constitute a large fraction of the total Dark
Matter (DM) today.
