I have just started managing a website created several years ago without my participation in Joomla 2.5. I need to change titles on several pages which are created using customized templates and I am cannot understand how it works.

The page is under menu item "Network Partners" which is assigned with a template "HULTIN-Clients", it has a title "Clients" which I need to change because it is incorrect. The page shows articles from a particular category, each article when opened also has incorrect title "Clients". Every time when I create new menu item and assigned it with a template "HULTIN-Clients" creates the title which I need to change. I attach the image for the demonstration. I should note that the website is maintained in three languages and depending on the language for the menu, the title changes the language too.
It is very very important for me to understand how it works, I would appreciate if someone could help me
