Retrofitting languages into English-based Install
To change it to the local language you do not need to make it a multi-lingual site as far as CiviCRM is concerned? I assume you mean that you installed the language pack. If you then want to change the language of your CiviCRM install you go to Administer/Localization/Languages,Currencies,Locations and change the language to what you want it to be. Unless I have completely misunderstood your question, but then you might want to expand a little on what you want exactly :-)