Disabled World, Sign Language and Assistive Hearing Devices ([Internet, 2020-07-20](https://www.disabled-world.com/disability/types/hearing/communication/))
EXP: in the narrow sense; often used as antonym of "written language"
after Wikipedia, "Spoken language" ([Internet, 2020-07-20](https://en.wikipedia.org/wiki/Spoken_language))