Algorithmic Text Generation

Design a C# class library that generates textual commentary about two sequential data points. There should be a level of syntax variations in the text if the algorithm is applied to the same data more than once. The more number of variation, the better the algorithm. Related data points will also be available to make the analysis deeper. Related points include changes drivers (why the first point changed to become the second point in the sequence) and the composition of the two points. The depth of the analysis should be controllable.