1. A system for building an interface that receives and responds to varied natural language expressions, the system comprising: at least one hardware processor; and at least one executable module that, when executed by the at least one hardware processor, builds at least one data structure comprising a plurality of sets of data fields that contain a plurality of concept symbols, wherein the plurality of concept symbols comprise a plurality of elementary concept symbols, wherein each of the plurality of elementary concept symbols corresponds to a natural language element, and a plurality of compound concept symbols, wherein each of the plurality of compound concept symbols corresponds to a pair, wherein the pair comprises one of a first elementary concept symbol and a second elementary concept symbol, an elementary concept symbol and a compound concept symbol, or a first compound concept symbol and a second compound concept symbol.