Over the years a variation of tests has been conducted within the various international surveys, as ESS, EVS and ISSP. Both at the international and national level tests regarding the wording of the questions and the response categories have been conducted. This study provides on overview of these language tests. Very often multiple tests are conducted on the same main question (versions A, B, etc), which are all included. More information on these variables is provided in the document "Translation and question format experiments - comparing the various wording and language tests".