What can be a sign of severe hearing loss?

Difficulty in hearing normal conversation is indeed a sign of severe hearing loss. Individuals experiencing severe hearing loss often struggle to discern speech even when it's spoken at a normal volume. This can severely impact communication and social interactions, as they may not reliably hear what others are saying, leading to feelings of isolation or frustration.

The other options suggest varying levels of auditory perception that would not typically align with severe hearing loss. For example, the ability to hear loud sounds might indicate some level of hearing capability, while an increased ability to perceive whispers is unlikely in someone with severe impairment. A normal reaction to environmental sounds would also suggest that the person has sufficient hearing ability, contradicting the presence of severe hearing loss.