To understand what Cross-language information retrieval involves it is necesary to know what it means. Retrieval is a sinonim of the word find in this context, which means that this subject is in charge of finding information despite the language of the document.
'Cross-language information retrieval (CLIR)is a subfield of information retrieval dealing with retrieving information written in a language different from the language of the user's query. For example, a user may pose their query in English but retrieve relevant documents written in French.
The first workshop on CLIR was held in Zurich during the SIGIR-96 conference. The proceedings of this workshop can be found in the book Cross-Language Information Retrieval (Grefenstette, ed; Kluwer, 1998) ISBN 079238122X. Workshops have been held yearly since 2000 at the meetings of the Cross-Language Evaluation Forum (CLEF), see http://clef.iei.pi.cnr.it:2002.
A resource page for CLIR maintained by Doug Oard can be found at http://raven.umd.edu/dlrg/clir/