Can I set lang-attribute for each web differently?

According to System.VarLANG one can set the language tag for browsers in the configure:

If {UseLocale} is enabled, it is calculated from the configure setting of {Site}{Locale}. Otherwise it defaults to en (English).

This is added into each html-files as follows:

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="%LANG%" lang="%LANG%">

Question

Is it possible to add this setting to each web differently, like when you have a wiki in several languages, separated by webs? Maybe setting in WebPreferences? Or is the only workaround setting this tag into the TopicViewTemplate? If so, how can I do that? I doubt that ADDTOZONE can do this, but I'm not so familiar with it.

Note: I am not talking about the language used for the interface, which is displayed with LANGUAGE: This Fowsiki is using "en".

Answer

I simply tried - and it worked. I added the following line to my WebPreferences, and now all the html pages have the correct language tag in their lang-definition: