Final answer:
The percentage of spoken words we never hear is not precisely quantifiable, but it can increase with hearing loss, particularly for frequencies above 8000 Hz.
Step-by-step explanation:
It's challenging to quantify the exact percentage of spoken words we never hear, as it can depend on individual hearing abilities and the environment. However, humans typically do not use their full range of hearing, especially for frequencies above 8000 Hz, which are seldom necessary for understanding conversations or enjoying music. Significant hearing loss can result in missing out on a higher percentage of spoken words. For example, a person with a 60-phon hearing loss will have difficulty understanding normal speech volumes and may find higher-pitched voices, like those of many females, more challenging to comprehend.