1. A computer-implemented method, comprising: receiving, at a client device, a document for a web page, the document comprising document text in a first language to be displayed on the client device; displaying, at the client device, the web page in web browser software executing at the client device, wherein the web page includes the document text of the document; identifying, at the client device, a second language to which the document text may be translated; determining, at the client device, whether the second language is different from the first language; displaying, at the client device, a translation header as part the web page above a portion of the document text to be translated when the second language is determined to be different from the first language, the translation header including (i) a selectable option to translate the portion of the document text from the first language to the second language and (ii) text in the second language describing the selectable option; and in response to a selection of the selectable option: identifying, at the client device, the portion of the document text to be translated; sending a request from the client device to a translation server to translate the portion of the document text from the first language to the second language; in response to the request, receiving at the client device translation data including a corresponding translated portion of the document text in the second language; and displaying, at the client device, the translated portion of the document text of the document as part of the web page.
1. A computer-implemented method, comprising: receiving, at a client device, a document for a web page, the document comprising document text in a first language to be displayed on the client device; displaying, at the client device, the web page in web browser software executing at the client device, wherein the web page includes the document text of the document; identifying, at the client device, a second language to which the document text may be translated; determining, at the client device, whether the second language is different from the first language; displaying, at the client device, a translation header as part the web page above a portion of the document text to be translated when the second language is determined to be different from the first language, the translation header including (i) a selectable option to translate the portion of the document text from the first language to the second language and (ii) text in the second language describing the selectable option; and in response to a selection of the selectable option: identifying, at the client device, the portion of the document text to be translated; sending a request from the client device to a translation server to translate the portion of the document text from the first language to the second language; in response to the request, receiving at the client device translation data including a corresponding translated portion of the document text in the second language; and displaying, at the client device, the translated portion of the document text of the document as part of the web page. 2. The method of claim 1 , wherein: the document text comprises body text of respective email messages, and the body text are displayed as representations of the email messages; identifying the portion of the document text to be translated comprises identifying body text of a first email message of the email messages to be translated; determining that the second language is different from the first language comprises determining for the body text of the first email message that the second language is different from the first language; sending the request from the client device to a translation server to translate the portion of the document text comprises sending a request to translate the body text of only the first email message; receiving the translation data including a corresponding translated portion of the document text in the second language comprises receiving translation data including translated body text of the first email message in the second language; and displaying the translated portion of the document text of the document comprises displaying the translated body text of the first email message and the body text of a remainder of the email messages.