The Akismet service works also with non-English posts.
If the spammy text is already contained in the Akismet service database, the result of the spam check is positive.
If it's not there yet, the result of the spam check is negative.
(I've simplified the process, a lot of other criteria are analyzed, following a proprietary algorithm).
In the case of a negative check, you should submit to the Akismet service the spammy text (to "help it" to recognize the spammy post the next time), invoking the submit_spam API.
The q2a Akismet plugin v2b3 declares a function ("public function submit_spam", file akismet.class.php) that contains the API invocation that should be executed.
But, if I'm not wrong, that function is never invoked by the plugin code.
The plugin invokes "only" the comment-check API , that is the API that check if the content of the post is spammy or not (see the first check above).
Conclusion :
the plugin should be extended, to include for example a "spam" red icon under every post (question, answer, comment - such as the "flag" icon, in the question page), that, following precise criteria (eg : an admin or more than X users have clicked on it), should invoke the submit-spam API (it could also be placed in the moderation queue).
An alternative would be that of invoking the submit-spam API *manually* (eg. : self-made php)
Another alternative is that of waiting (and hoping) that the spammy post will be submitted to the Akismet service by another user ........ 
