By Sarah Horton and David Sloan — Some people have disabilities that affect the auditory channel and are not fully correctable through a hearing aid. The phrase “hard of hearing” categorizes conditions that cause people to have some hearing loss, which may reduce their ability to distinguish some sounds from others or to hear sounds of a particular volume or frequency. Complete hearing loss is usually referred to as deafness.
People who are deaf may identify as Deaf (with a capital “D”), indicating membership of a culture of Deafness, connected through a shared language, usually a sign‑based language. Some people who are deaf, particularly those who were prelingually deaf or lost their hearing during childhood, use sign language as a primary means of communication, and may have lower literacy in text‑based languages.
Accessibility needs of people who are deaf or hard of hearing include the ability to:
- Access alternative versions of audio content, for example, through text or sign language interpretation.
- Adjust the display of text alternatives for audio.
- Access sign language versions of text content.
- Adjust the volume level of audio content.
- Use headphones or hearing aid compatible (HAC) devices to access audio content.
It’s worth noting that sign languages use distinct syntax, grammar, and vocabularies and have evolved in different patterns compared to spoken language. So don’t assume that because two countries may share a common spoken or written language, their sign languages are also mutually intelligible. For example, American Sign Language (ASL) is more closely related to French Sign Language (LSF) than British Sign Language (BSL). This means that serving a multilingual audience may require sourcing and providing content in multiple sign languages, just as you would need to consider a strategy for internationalization and localization of text and spoken content.
From Horton, S., & Sloan, D. (2024). What Every Engineer Should Know About Digital Accessibility. CRC Press, Boca Raton, Florida.
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