  The straightforward description of q-deformed systems leads to transition
amplitudes that are not numerically valued. To give physical meaning to these
expressions without introducing {\it ad hoc} remedies, one may exploit an
"internal" Fock space already defined by the q-algebra. This internal space may
be interpreted in terms of internal degrees of freedom of the deformed system
or alternatively in terms of non-locality. It is shown that the $q$-deformation
may give stringy characteristics to a Yang-Mills theory.
