Deafness is not what it used to be. Nor has it ever been just one thing, but many. Typically it refers to those who cannot understand speech through hearing alone, with or without amplification. Colloquially, it may also refer to any hearing impairment, as when a person is described as “a little deaf.” Professionals in education and communication sciences distinguish prelingual from postlingual deafness, in recognition of their different implications for speech and language learning. Within the deaf community, in contrast, the term “deaf,” as well as its signed equivalent, usually refers to people who identify culturally as deaf, and is sometimes capitalized (“Deaf”) to distinguish the culture from the audiological condition. In the nineteenth-century United States, culturally deaf people frequently referred to themselves as “mutes,” while educators used “semi-deaf” as a synonym for hard of hearing, “semi-mute” for the postlingually deafened who retained intelligible speech, and “deaf-mute” or “deaf and dumb” for the prelingually deaf. Deafness also has long been a common metaphor for a refusal to listen or to learn, as when the French writer Victor Hugo declared that “the one true deafness, the incurable deafness, is that of the mind” (qtd. in Lane 1984, ix). In 1772,...