Have you ever lost your voice? How did you handle that? Perhaps you carried a notebook and pen to scribble notes. Or jotted quick texts on your phone.
Have you ever traveled somewhere that you didn't speak or understand the language everyone around you was speaking? How did you order food, or buy a train ticket? Perhaps you used a translation phrasebook, or Google translate. Perhaps you relied mostly on physical gestures.
All of these solutions are examples of communication methods — tools and strategies — that you may have used before to solve everyday communicative challenges. The preceding examples are temporary solutions to temporary challenges. Your laryngitis cleared up. You returned home, where accomplishing daily tasks in your native tongue is almost effortless. Now imagine that these situational obstacles were somehow permanent.