One Google engineer David Signleton, who used iPhone, wasn’t happy with how Google Translate page worked on it and decided to create a new iPhone-specific version of the site. Another engineer Allen Hutchison joined forces with David to develop a better site. The new Google Translate site is optimized for speed and supports translations in all of the languages that the regular site does. The website uses Google’s Language API which gives it the ability to automatically show any new languages. The site will store all of the old translations on your phone for quicker reference.
According to Ars Technica there are few problem when using the Translate site like Arabic characters are not properly displayed in Safari and iPhone users are automatically redirected to iPhone version and hence it’s more difficult to translate a full site.