variable rr:language?

Hello all,

Reading the specs of R2RML seems that using a column as an input for a
rr:language or rr:datatype may be not possible.

You can map columns to the data using rr:column and rr:template, but that
seems its not the case with rr:language or rr:datatype, as they only
support constants.

I'm adding a mapping example, commenting the way the a column could be used
to define a rr:language (but is not allowed to):

[] rr:objectMap [
  rr:column "NAME";                   # VALID
  # rr:template "{NAME}"@{LANG};      # NOT VALID

  rr:language "BG";                   # VALID
  # rr:language [ rr:column "LANG" ]; # NOT VALID

  rr:termType rr:Literal
];

I feel this is something R2RML should be able to do.

I'm missing something? Is there a workaround to use a column as language?
My last option is to include the language within the actual data and later
post-process it to extract the language and tag it correctly.

Thanks,
Guillermo