Using CONSTRUCT to add language tag?

[Bob DuCharme]

Does anyone have any suggestions about how a SPARQL CONSTRUCT query 
might add language tags without using extensions? The query below works 
with ARQ, but it uses the Jena extension LET and the concat() function:

 PREFIX anrecs: <http://www.snee.com/ns/analystRatings#>
 PREFIX fn: <http://www.w3.org/2005/xpath-functions#>
 CONSTRUCT {
   ?company anrecs:company ?coNameWithLanguageTag .
 }
 WHERE {
   ?company anrecs:company ?coName .
   LET (?coNameWithLanguageTag := fn:concat(?coName,"@en")) .
 }
thanks,

Bob