Summarized test results:
Translate attribute and online translation services

Intended audience: users, XHTML/HTML coders (using editors or scripting), script developers (PHP, JSP, etc.), CSS coders, Web project managers, and anyone who wants to know how HTML escapes work in current browsers.

Updated

These tests check whether online machine translation systems recognise the HTML5 translate attribute when processing text for translation.

Summary & conclusions

Both Google and Microsoft online translation services recognised the translate attribute when it was set to no, and left the appropriate text untranslated.

Neither service recognised the translate flag set to yes inside an element with the translate flag set to no as being a signal that that bit of text should be translated.

Latest results

This is a snapshot of the results in the W3C Test Framework taken on

Any browser
default text, Google A file with no translate attribute will be translated by Google's online service. yes / . / .
default text, Microsoft A file with no translate attribute will be translated by Microsoft's online service. yes / . / .
translate no on html, Google When translate=no on the html element no content will be translated by Google's online service. yes / . / .
translate no on html, Microsoft When translate=no on the html element no content will be translated by Microsoft's online service. yes / . / .
translate no on one p, Google When translate=no on a p element the content of that element will NOT be translated by Google's online service. yes / . / .
translate no on one p, Microsoft When translate=no on a p element the content of that element will NOT be translated by Microsoft's online service. yes / . / .
translate yes on one p, Google When translate=yes on a p element the content of that element WILL be translated by Google's online service. yes / . / .
translate yes on one p, Microsoft When translate=yes on a p element the content of that element WILL be translated by Microsoft's online service. yes / . / .
translate null on one p, Google When translate is set to the null string on a p element the content of that element WILL be translated by Google's online service. yes / . / .
translate null on one p, Microsoft When translate is set to the null string on a p element the content of that element WILL be translated by Microsoft's online service. yes / . / .
translate no on span, Google When translate=no on a span element the content of that element will NOT be translated by Google's online service. yes / . / .
translate no on span, Microsoft When translate=no on a span element the content of that element will NOT be translated by Microsoft's online service. yes / . / .
translate yes on span, Google When translate=yes on a span element in a context where translate has been set to no, the content of that element WILL be translated by Google's online service. . / no / .
translate yes on span, Microsoft When translate=yes on a span element in a context where translate has been set to no, the content of that element WILL be translated by Microsoft's online service. . / no / .