Add translation only for a particular content type
It's by design...

Drupal Content translation using modules like i18n and locale works for complete site... For example if you are using Arabic language and if you add a arabic translation for a particular node, if you are viewing arabic version of node complete site changes from right to left..

As a work around..If you just want to add translations i would suggest use modules like Entity reference and node clone to connect english version with other versions and use select box to choose language.. You need to add links to redirect user to other versions based on above reference logic.. Keep in mind by implementing above you will loose Drupal powerful Multilingual feature..