adding lang to the call

call-for-nodes.html

@@ -70,6 +70,7 @@ we imagine that all person present reflects on hacking practice and production.
      AUTHOR:      Your nick / identity
      DAY:         When you prefer to do the talk (optional)
      NEEDS:       Projector, table, pen, keyboards, humans, ...
+     LANGUAGE     The lang you may use to speak during your talk 
      DESCRIPTION: Try to define what will you talk about 
                   ....