  We generalize the construction of multitildes in the aim to provide
multitilde operators for regular languages. We show that the underliying
algebraic structure involves the action of some operads. An operad is an
algebraic structure that mimics the composition of the functions. The involved
operads are described in terms of combinatorial objects. These operads are
obtained from more primitive objects, namely precompositions, whose algebraic
counter-parts are investigated. One of these operads acts faithfully on
languages in the sense that two different operators act in two different ways.
