[TYPO3] strange problem with languages

[Xavier Perseguers]

Hello,

After deploying a test website I had on my laptop (by recreating step by 
step on the production server), I encounter a strange problem with 
languages. I have four languages and I output the value of 
sys_language_uid to be sure. Changing the L parameter uses the 
sys_language_uid I defined with my typoscript. But texts are not 
translated. Or to be more precise, I get two different languages shown 
(English and French for instance) but I cannot get texts in Italian nor 
German. If I clear the cache and first go to German, then it's OK, I can 
get Italian too but then I cannot access French anymore nor English, it 
displays text in one of the other languages.

It's a bit strange and I do not see what I have missed between my test 
server and the productive one. Any hint?

-- 
Xavier Perseguers
http://xavier.perseguers.ch/en