xml:lang vs xs:language

Hi,

We are having a discussion on whether to use "xml:lang" as an attribute on a new element that we are defining in our xsd or whether to make a new element with type "xs:language".

For e.g (not syntactically correct but just to give you an idea)

<Newelement attribute xml:lang> </Newelement>

OR

<Newelement > 
<have another sub element with xs:language type>
</Newelement>

Is there any guidance on which one to use?

Thanks.