Perhaps you should try some spelling variations:
language acquistion » langage acquisition, language question, language action
language attrition » language cognition, language action, language description
language detection » language definition, language description

Try widening your search to All Fields.

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: %((language acquisition) OR (((((language acquistion) OR (language attrition))) OR (language detection)))) AND development%22.
• Adding a wildcard symbol may retrieve word variants: %((language acquisition) or (((((language acquistion) or (language attrition))) or (language detection)))) and development%22*.