I'm wondering would could be a great way to develop a dynamic site, with the potential of adding languages and never altering the opening site with this.

You pointed out you had been using zend which means you should have the ability to implement this.

Here you decide to go Zend_Translate.

http://framework.zend.com/manual/en/zend.translate.introduction.html

Ive not tried on the extender myself however it states within the paperwork it allows you to definitely translate a view using whatever language adapter you want to make use of.

Better is by using Content management systems like Wordpress , zoomla yet others.