Translations ? Which language 1st?

[Poker-Business]

I have a issue related to translations so i`m just gonna post it here:

We are about to translate our site to several different languages soon.
I was talking with one company and this guy advised me to go with his language system with subdomains. But the fact is he wants to put english version, which was so far www.siteaddress.com to en.siteaddress.com like all other translations because of better usage and webmaster maintenace. He said this will be done through some sessions and "en" set on primary www.siteaddress.com but if for example user selects german language and closes the website and next time he opens it, the german version will appear there. He also said that keeping english version on .com could result in some bugs in future system updating, so it is much better to do it like this.
I like this system, but i was wondering how this will affect SEO, since so far we have done some SEO work for english version, which is on .com address now. He said everything will be okay regarding this too, so i am asking if someone had any similar experiences with this or if you have an advice regarding this?

Best regards,
Rok

[Jeremy]

I would just leave the english version on the .com. If you move that version to a subdomain such as .en, you will need to 301 redirect all the old pages to the new sub-domain and risk something getting screwed up there.

I guess it can be done, and for all the new languages, the subdomains make sense. I guess I don't understand the purpose of doing it on the existing site if english is your primary language. It sounds like something the coder wants to make the CMS function better......still seems a bit confusing though.

[Poker-Business]

Thing is he is somehow putting all this into root directory and then using some programming to connect all this. Now what i am still not sure about is this english version. I mean if he transfer so far used www.site.com to en.site.com what will happen with all the seo links and how will all this affect all the seo work we have done in the past for www.site.com ? And how will this affect the future work? Also what is this 301 re-direct and if its needed here? I heard redirects are bad for seo.

regards,
Rok