Symptoms
There are several languages enabled and activated, but the multilingual selection (e.g. plan name, plan short and long description) is missing in the control panel.
Cause
That is a side-effect of the bug #PBA-36390 ("It's possible to work with PBA even with expired password").
Resolution
In BA there is the password expiration policy :
Home > System > Settings > Security
you either need to disable the policy (anyway it is valid only for the direct logins to BA) and set it in OA if required (System > Settings > Security > Password Expiration Policy) or you need to make sure all the users changed the passwords. For those who changed the password, the multi-locale is supposed to appear and the user will be able to edit the plan names when logged in under any of the locales.