Can someone point me to description of Watson's sentence realization API? I guess it could be called the semantics-to-text part. Realizers like FUF/SURGE, KPML/

Can someone point me to description of Watson's sentence realization API? I guess it could be called the semantics-to-text part. Realizers like FUF/SURGE, KPML/Nigel, and RealPro are quite complex to use. SIMPLENLG and OpenCCG are simpler, but the results I saw were not impressive. The demos of Watson are quite good, so I'm really interested to see how it performs on operations more complex than delivering factoids.