I believe that the Maker of everything, including language, can choose to have many names, so why is only the one used by JWs?
Jehovah is his personal name as opposed to the titles he is known by. Much like 'Prince Charles' has the title of Prince, but his personal name is Charles... 'Prince' doesnt really define his personality whereas 'Charles' is personal to him. And if he was only ever known or refered to as 'Prince', it would be hard to distinguish him from the many other 'Princes' who have the same title.

We still sometimes refer to God by his titles such as God, Lord, Father etc. But when you think about it, there are many god's, lords and fathers, so in order to identify whom we are talking about we use his personal name. In hebrew his name is YHWH and it means 'Become' and in hebrew its translated to mean 'He causes to become'

So the importance of his name is in the fact that it identifies him as the creator.