Perhaps you should try some spelling variations:
"bulgaria language" » "bulgarian language", "bulgare langue"
"bulgaria average" » "bulgaria overview", "bulgaria stage", "bulgaria energy"
"nigeria language" » "nigerian languages", "sumerian language", "media language"

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (((("bulgaria language") OR ("bulgaria average"))) OR ("nigeria language")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"bulgaria language\") OR (\"bulgaria average\"))) or (\"nigeria language\"))".
• Removing quotes may allow a broader search: (((( bulgaria language ) OR ( bulgaria average ))) or ( nigeria language )).
• Adding a wildcard symbol may retrieve word variants: (((("bulgaria language") OR ("bulgaria average"))) or ("nigeria language"))*.