[TYPO3] Switch default FE language

[Florian Schupp | FORMER 03 GmbH]

Hi guys,

the site we're working on has two lanuages right now. German as default 
language and English. Now our customer has realized, that the default 
language should be English.

What do you think must be done to switch the two languages, meaning that 
German becomes a alternative page language?

Thanks a lot in advance, I've got my difficulties to estimate the cost 
for this action.

Cheers Florian