This text gives a first draft of the definition of $θ$-duadic codes where θ is an au-tomorphism of $F q$. A link with the weakly self-dual $θ$-cyclic codes is established. A construction and an enumeration is provided when q is the square of a prime number p. Lastly a parametrization of irreducible skew polynomials of $F p 2 [X; θ]$ is given as an extension of this construction.