  We calculate the three-point function for primordial scalar fluctuations in a
single field inflationary scenario where the scalar field Lagrangian is a
completely general function of the field and its first derivative. We obtain an
explicit expression for the three-point correlation function in a
self-consistent approximation scheme where the expansion rate varies slowly,
analogous to the slow-roll limit in standard, single-field inflation. The
three-point function can be written in terms of the familiar slow-roll
parameters and three new parameters which measure the non-trivial kinetic
structure of the scalar field, the departure of the sound speed from the speed
of light, and the rate of change of the sound speed.
