Oliver Sacks describes that there is more voice in the signing of the hearing impaired. Sacks spends most of his time demonstrating that sign is not at all a pantomime language, but a “fully formalized and grammaticized” (122), left-hemisphere language. That said, “One has only to watch two people signing to see that signing has a playful quality, a style quite different from that of speech. Signers tend to improvise, to play with signs, to bring all their humor, their imaginativeness, their personality, into their signing…”
“Signing is not just the manipulation of symbols according to grammatical rules but, irreducibly, the voice of the signer–a voice given a special force, because it utters itself, so immediately, with the body. One can have or imagine disembodied speech, but one cannot have disembodied Sign. The body and soul of the signer, his unique human identity, are continually expressed in the act of signing.” (Oliver Sacks. Seeing Voices: A Journey into the World of the Deaf. New York: Harper, 1990. 121-23.)
J.A. Arlow describes a child raised by deaf/signing parents, reading “voice” in their faces: “He became extremely sensitive to intentions and meanings which can be communicated through expressions on the face… Like his [deaf] father, he was particularly sensitive to people’s faces and could make good judgments about the intentions and sincerity of those with whom he was engaged in business… He felt that in ordinary business negotiations he had a serious advantage over his opposite numbers.” (Arlow, J. A. “Communication and Character: A Clinical Study of a Man Raised by Deaf-Mute Parents.” The Psychoanalytic Study of the Child 31 (1976): 139-63.)