"Text Analysis" is a fancy term that simply means identifying important sounding phrases in a textual description of a domain. Important noun phrases—user, owner, controller, buffer, etc.-- are often modeled by classes, important verb phrases—uses, has, owns, controls, etc.-- are often modeled by associations. Phrases suggesting classifications—kinds, types, is one of, etc.—are often modeled using generalization. Phrases suggesting assemblies— is part of, is made from, etc.—are often modeled using composition. Phrases suggesting collections—contains, holds, etc.—are often modeled using aggregation.
See also http://en.wikipedia.org/wiki/Entity-relationship_model