How to achieve vietnamese language support for SAP?

Dear all,

It's easy to add languages which are natively supported by SAP like Japanese, French...

I wonder what are the things to do when we need language enablement for languages like vietnamese which are not yet supported by SAP.

What we want to achieve.

When we logon, select VN as the logon key.

Then in the application, it show our language text instead of DE or EN.

Thanks

Giang