Test your hearing:

At some point you become aware of this: "I can still hear pretty well, but sometimes I can’t make out quiet voices." Or: "I didn’t hear the announcements at the airport properly again." Or: "I’ve started eating alone in the canteen, I can’t hear my coworkers speaking over the background noise and having a conversation is too much of an effort for me."

Especially in a noisy environment, it is the sounds in the higher frequency range that you find harder to understand:

• Women’s and children’s voices, for example.
• Consonants such as s, f, sh, and t are spoken more softly and quietly. With these gaps in what you can distinguish, you can indeed "hear what people say", but you can no longer understand it properly or fully.
• This leads to misunderstandings: table not fable, heating not seating, confine not consign.

And then, when the first difficulties arise with hearing or understanding, you usually subconsciously try to compensate for them by making a greater effort:

• You start to pay attention to people’s lip movements and expressions, where you are able to read what you can no longer hear.

• You fill in the gaps in what you understand by putting in what the other person might have said, relying on deductive reasoning and intuition.

• You pay close attention to the context of a conversational situation or announcement in order to compensate for what you fail to hear.

• You constantly scan your memories for helpful hints: What was this person talking about before? What did he say last time?