  We use the delta N-formalism to describe the leading order contributions to
the primordial power spectrum, bispectrum and trispectrum in multiple-field
models of inflation at leading order in a perturbative expansion. In slow-roll
models where the initial field fluctuations at Hubble-exit are nearly Gaussian,
any detectable non-Gaussianity is expected to come from super-Hubble evolution.
We show that the contribution to the primordial trispectrum can be described by
two non-linearity parameters, tau_{NL} and g_{NL}, which are dependent upon the
second and third derivatives of the local expansion with respect to the field
values during inflation.
