  We discuss some model-independent implications of embedding (aligned) axionic
inflation in string theory. As a consequence of string theoretic duality
symmetries the pure cosine potentials of natural inflation are replaced by
modular functions. This leads to "wiggles" in the inflationary potential that
modify the predictions with respect to CMB-observations. In particular, the
scalar power spectrum deviates from the standard power law form. As a
by-product one can show that trans-Planckian excursions of the aligned
effective axion are compatible with the weak gravity conjecture.
