intex basic tools are Finite State Transducers that are represented by graphs. We show how these graphs are used to describe various linguistic phenomena. Graphs that represent elementary phenomena are re-used in other, more complex, graphs. Thus, linguists can actually build massive libraries of graphs that handle a variety of phenomena, from the vocabulary and the morphology to the syntax of natural languages. intex provides linguists with tools to easily edit, maintain, debug and validate any piece of the description by applying graphs, or sets of graphs, to large texts.