The Language picklist lists all the languages enabled in the specific Salesforce org.

After choosing a language, translations can be defined for all available strings in all the supported features listed above, or for specific strings. Specific strings can be retrieved by choosing the appropriate Process Type, and optionally with a specific Process Name. Specific strings can also be retrieved by entering all or part of the translatable string in the Search For Master Text field. This search condition can be applied in combination with Process Type and Process Name.

Clicking the Get Translations button loads the matching strings for the defined search criteria. The search for master text is a contains search.