In the last year she has acquired a whole new set of skills and the vocabulary to go with them. She knows, for example, that "bullnose" is the term for tile that curves at the top of a bathtub, that a "baker" is a machine that bends aluminum siding, and that "mud" is the material applied between sheets of drywall. At a time when many American women her age are employed outside the home, Donovan, wife and mother of two young children, also is in the full-time work force, but she is volunteering that time as executive director of Habitat for Humanity Lake County, an organization dedicated to providing affordable housing for the poor.