DOCBOOK: multiple lang in one sgml source file

hi all

I'm writing a document in two language, Japanese and English.  Is
there a way to have both language in one docbook source file? and pick
a language at the conversion time with jade?

eg.
<chapter>
<para lang="ja">some japanese paragraph...</para>
<para lang="en">The translated previous paragraph</para>
</chapter>

I'm pretty sure that I have seen this topic on the list, but I don't
remember weather it was good idea to do it or not, and even can't find
the mail in the archive.

Could someone just dropping me a line with title or message-id for the
mail, if you know it?

Thanks,
--
         yashi