  There is a one-to-one and onto correspondence between the class of numerical
semigroups of depth $n$, where $n$ is an integer, and a certain language over
the alphabet $\{1,\ldots,n\}$ which we call a Kunz language of depth $n$. The
Kunz language associated with the numerical semigroups of depth $2$ is the
regular language $\{1,2\}^*2\{1,2\}^*$. We prove that Kunz languages associated
with numerical semigroups of larger depth are context-sensitive but not
regular.
