1. A method, in a data processing system comprising a processor and a memory, the memory comprising instructions which are executed by the processor to configure the data processing system to implement a natural language content (NLC) disambiguation engine, the method comprising: identifying, by the NLC disambiguation engine, in a corpus of natural language content, a portion of natural language content (NLC) that is determined to be ambiguous with regard to a context of the portion of NLC, thereby identifying an ambiguous content portion; comparing, by the NLC disambiguation engine, the ambiguous content portion to private content information associated with a source of the ambiguous content portion, wherein the private content information is content information accessible to users and resources associated with the source and is not accessible to users or resources that are not associated with the source; identifying, by the NLC disambiguation engine, a domain of the ambiguous content portion based on a domain of a matching portion of the private content information; and performing, by the NLC disambiguation engine, a clarifying operation that clarifies the ambiguous content portion based on the identified domain of the ambiguous content portion to thereby generate a clarified content portion for processing by a cognitive operation of a cognitive system.