"When we hear a noise, the brain analyzes the incoming stimuli, asking itself: Is that weird yammering human? Is it a syllable, a real word, just nonsense sounds? If it resembles speech, the brain conjures up the memory of how certain words sound, associates them with meaning, and furnishes instructions on how to use the muscles of the tongue, throat, lips, and mouth to dispatch a reply.

"In so-called convergence zones, cargo from the senses combines with emotions, resemblances, a tangle of memories, and other mental spices. As neural traders hobnob (wiring and firing together), they grow stronger ties in the process, establishing a quick route for future trade. The brain relies on such guilds of neurons firing in synchrony, but they don't have to be neighbors. They don't even have to share the same hemisphere. Still, they forge vast assemblies of cells. One such convergence zone in the parietal lobe, gravely damaged during Paul's stroke, is associated with drawing meaning and emotion from language, with providing music's rhythmic enchantment, numbers' clout, writing's constellations, telling left from right, directing thoughts outward to the bright spangled world, and deflecting thoughts inward to judge a feeling or hatch a plan. Adding to the carnage, adjacent cells that spur movement can be injured, too. It's the equivalent of knocking out a state's electrical grids. After that comes a cascade of silently detonating disabilities.

"My mind raced. In an instant, Paul had moved to a land of foreigners, whose language he didn't speak and who couldn't understand him. He'd become the unspoken, the unspeakable. In our most talkative of worlds, where lovers coo and confide, friends and family chatter, employers dictate, stores pitch, and all the ready forms of entertainment for the sedentary or sick (TV, books, doctor's office magazines, newspaper, movies) babble language. Suddenly he could not comment, share thoughts, voice feelings, describe hurts or desires, ask for help.

"Over the next day, Paul slept a lot, thank heavens, and, in a stupor, I dragged home to shower and nap, and also cancel upcoming book tour events. I needed to let the venues know so that, with any luck, people might see the last-minute 'canceled because of family illness' postings. But I still felt guilty imagining them arriving at events only to find a cryptic sign awaiting them. I emailed editors who expected work to be turned in, and canceled all assignments. My project lay in a narrow bed across the lake."