Biological systems, like your Achilles tendon or your kidneys, work in another
way, they are usually made of many small parts, and usually their performance
degrades gracefully, trying to avoid catastrophic shut-downs.
For example usually a large tendon rips itself progressively, and such ripping
adsorbs lot of energy, hopefully enough to keep some tendon left. Then if a
little amount of tendon is left, new tendon can grow along it, using it as
The language areas of your brain, when they get old, produce words slowly or
partially wrongly, but they usually don't stop talking.