This paper introduces XMG2, a modular and extensible tool for various linguistic description tasks. Based on the notion of meta-compilation (that is, compilation of compilers), XMG2 reuses the main concepts underlying XMG, namely logic programming and constraint satisfaction, to generate on-demand XMG-like compilers by assembling elementary units called language bricks. This brick-based definition of compilers permits users to design description languages in a highly flexible way. In particular, it makes it possible to support several levels of linguistic description (e.g. syntax, morphology) within a single description language. XMG2 aims to offer means for users to easily define description languages that fit as much as possible the linguistic intuition.