I have tried implementing the languageversioning scheme described in the book Multilingual 1:1 sites by torleik. Along the way I encountered a few problems.

Most of the problems where probably because it is written for v3. Is Torleik around to write a v4 edition? I could also do it, but I don't have permission atm. The tutorial should be relevant for a lot of users, and I think it only needs a few tweaks.

The issues that I noted while going through the 7 steps where:

Validation of XSLT example failes because of missing quotes after xmlns:xsl

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet
      version="1.0"
      xmlns:xsl=http://www.w3.org/1999/XSL/Transform
      xmlns:msxml="urn:schemas-microsoft-com:xslt"
      xmlns:umbraco.library="urn:umbraco.library"
      xmlns:kv_trans ="urn:kv_trans"
      exclude-result-prefixes="msxml umbraco.library kv_trans">
<xsl:output method="xml" omit-xml-declaration="yes"/>
<xsl:param name="initlang">en</xsl:param>
etc. etc.

 
Wrong DLL

The text states "and include a reference to the umbraco.dll file". But it is the cms.dll that needs referencing.

Invalid parameter for GetByCultureCode

In the XSLT extension class the call "Language.GetByCultureCode(language)" fails because it is not getting a correct culture code. In the example it is always e.g. "en" or "da", so the country part is missing ("en" should be "en-US").
This took a while for me to figure out :-/

Lack of complete example

It would be nice with a more complete example. There are a lot of XSLT snippets, but if you are new to Umbraco it can be a bit hard to figure out where put these snippets (in the template, in the XSLT libraries or?)