Multilingual web site based on different web pages extensions?

[eluser]DimCI[/eluser]
The subject is clear imho.

been trying to implement such m/ling.site draft. E.g. english pages are '.htm', russian - '.shtml', ukrainean - '.html', etc... (if needed). Each page has a small menu to switch current lang.

Does anybody have any experience in this direction? If yes, tell me, please, your considerations and flashbacks about this idea having in mind seo impact, performance, and other important issues.

Waste of time or not?

Thank you