The hearing is essential to communicate. It is through hearing that we learn how to speak our native languages in the first place. And to speak our first words when very little, we needed someone else to be patient enough to communicate with us as clear as possible, so we could slowly catch the words, understand their meaning and reproduce them. And we continue this process of hearing-understanding-reproducing for our whole lives, even if we never learn a second language (that's why for example, when someone moves from the city he/she grew up in, to another one where people speak with a complete different accent, after some years, this person starts to speak at least a little bit with this new accent). And this process works for both ways, as the more we communicate, the more we improve our hearing abilities.
So when a person suffers some sord of hearing disability (one that would require it to wear a hearing-enhancing device), it should also end up suffering a loss of its communication ability, because of the lack of practice of that mentioned process (hearing-understanding-reproducing). And, since it works for both ways, when this person starts to communicate less, it also affects its already depleted hearing ability. So both communicating and the collaboration of others are essential!