Supporting several languages

Hello,

I have a projects where I need to support a few pieces of documentation 
in several languages (nothing fancy here: english, french, german...).

I'm wondering  about the best way to support a single document in 
multiple langages. The  simplest way would be to use a file for each 
version, but I'm thinking that using a single document for each language 
would be easier to support.  In this context, each paragraph and title 
would be tagged with its language. Example:

<section>
<title><en>Hello</en><fr>Bonjour</fr><title>

<para>
<en>Some random text</en>
<fr>Du texte aleatoire</fr>
</para>

</section>

Then I would use a simple XSLT stylesheet to filter out all languages 
but one. I know  about the lang tag, but it doesn't really works in my 
case, since I want to put several versions of a document in the same file.

Advantages:
-- Less duplication of markup.
-- Easier to keep the different versions in sync.

Drawbacks:
-- More complex to manage if several people are working on the document 
at the same time: they must use CVS.
-- More complex to compile.

Comments? Problems I've overlooked?

Best Regards,
David Garnier