Another is that we can resolve ambiguities with language-independent world knowledge. This knowledge is reusable from one language to another. The form of an interlingua sentence is a labeled directed graph. This graph can be printed in a number of ways. Thus, main verbs are the heads of sentential clauses, and head nouns are at the root of noun phrases, etc.
P is an instance of a person.
A is an instance of eating. So much for format. We have 70,000 primitive concepts and a complex mapping between words and concepts. Our 70,000 concepts are hierarchically arranged so that statements concerning one concept may imply statements concerning another. The concepts are drawn from sources like WordNet.