Unlike others, uOGT allows users to translate selections of text by including them in a SPAN tag and with class 't'. Of course, like most of Google's web APIs(though this is unofficial), this one requires you to include a JavaScript file to the pages that you want to translate as well(you will also need to upload a server-side file). So is it going to take longer to download the pages that included with the JS file? No, it won't, because the file is so small - less than 800 bytes.