1. A system for processing samples of a target language, comprising means for generating modified versions of said samples or of fragments of said samples, wherein, said modified versions are generated by applying groups of modifications, said groups of modifications contain one or more modifications, one or more of said modifications can be applied in an independent fashion, said target language can be a foreign language or a native language, wherein said system can be used for different purposes, such as for example to present modified versions in order to assist in language comprehension and/or learning, to create data that will be used to generate said modified versions, or for other purposes.