Here is a picture of the "Translate this page" option in action:
You can prevent Google to show this "Translate this page" link, by using a simple meta tag in your page <head> tag:
<meta name="google" value="notranslate">
But most importantly, you may want Google Translate to exclude some part of your website such as menus or a portion of text. You can do this as well using class="notranslate" to a div, span or paragraph, like so:
[via blogsdna]
<span class="notranslate">The text you don't want Google to translate goes here</span>
[via blogsdna]