Initially i thought of doing it by changing portlet title in resource bundle of exploded war located into <wp_profile>
Then i found one way to do this via "Configure Portlet" setting
If you go to Portal administration - > Portlet Management - > Portelts - > and there you see a configure icon for every portlet.
Click on that icon, and there you find link "I want to set titles and descriptions."
click on this and then click on edit icon of your desired language title you want to change.
You will have options to change portlet title and description.
That's it, you are done with changing portlet title statically.
To change portlet title at Runtime, have a look at my article on
Changing Portlet title at runtime