To explain how query elements can be translated.
Please start the BEx QueryDesigner and open the query. On TAB Extended please get the UID and enter this UID into the selection field ELTUID in table RSZELTTXT. Now you can see all available texts for this element.
If you start the query with the language which is maintained in table RSZELTTXT then you see the RSZELTTXT-text. But if you logged on with a language which has no RSZELTTXT entries, then a default is taken (selection > name or technical name of keyfigure).
Please review the Online-Documentation below where you can find also information about "texts for characteristics":
Translating text elements
Currently to translate the text elements the only way to do this is to logon in the designer language in Query designer and enter the test elements. This will then be present for users using the query in that language.
Please note as of February 2014, I am currently working on a report to translate text elements.
Structure Element Texts and Their Language-Dependency