16. The system of claim 13 , where sending the request includes entering a uniform resource locator into a field of a presented translation interface and identifying the second language.
13. A system comprising: one or more computing devices configured to perform operations including: sending, using one or more processors, a request to translate a source web document from a first language text to a second language text; receiving a translated web document for display containing a translation of the source web document into the second language text; displaying the translated web document; and in response to interacting with a portion of the translated web document, displaying the first language text that corresponds to a portion of the translated web document in a graphical element overlaying the translated web document.