The TMGMT Memory is a module that complements Translator Management Tool (TMGMT). It adds translation memory allowing you to save money and time in cases where the content of a translation was already done before (Exact match), or also can provide candidate translations (Partial match) as help for translation providers like tmgmt_local.
Also if a content item currently changes in one field, it needs to be resubmitted as a whole to the translator. Without a translation memory, a translator is asked to perform the same translation again and again.
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.