200 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1946: 
cidentally, was an objective of the early researches of Alexander 
Graham Bell.) It suggests the possibility of printing words pho- 
netically and of the automatic retranslation of such printed symbols 
into understandable sound. It opens the way to the selective opera- 
tion of automatic devices by voice sounds. It promises to be particu- 
larly useful in the specialized fields of phonetics, philology, and music. 
But most immediately, and from humane considerations most import- 
antly, it opens a new avenue of help to the totally and severely deaf- 
ened—help to learn to speak, and for those who already speak, help 
to improve their speech. It is to this problem of aid to the deaf that 
we have first directed our efforts. 
It is too early to evaluate the results of these efforts with certainty. 
That there is a firm basis underlying the legibility of the visible 
speech patterns which have been obtained can hardly be doubted, but 
many questions remain concerning the design of practical translating 
equipment, the time and effort necessary to acquire a reading vocab- 
ulary, the effects of transmission and reception conditions on pattern 
legibility, and the special needs of the equipment for speech teaching 
and rehabilitation. These questions cannot and should not be 
answered hastily, even though they are naturally urgent to those 
afflicted with a serious hearing loss. ‘Their answering requires, dur- 
ing the developmental stages of the equipment, the cooperative efforts 
of the engineer and the groups concerned with the problems of deaf- 
ness. The purpose of the present paper is to introduce the subject 
of visible patterns of sound and to describe briefly some of the more 
general aspects of the work with them. 
In plate 1 are shown two forms of the new sound patterns. Both 
represent the same words—“This is visible speech”—and both show 
the three basic dimensions of sound—frequency, time, and intensity. 
It should be noted that the words associated with the different sec- 
tions of the pattern, are inserted at the top of the figure. Time extends 
horizontally, the total length of each record being roughly 214 seconds. 
Frequency is spread out vertically from substantially zero at the bot- 
tom of each record to about 3,500 cycles at the top. Intensity is shown 
by the varying shades of gray. Resolution of the frequency dimen- 
sion is the significant difference between this and other more familiar 
displays of sound such as the oscillogram. Such a display provides 
for the eye the frequency analysis which is natural in aural perception 
and necessary for an understanding of sounds. 
Patterns of the type illustrated by plate 1 (a) are of interest in 
studies of speech characteristics, while the type shown in plate 1 (0) 
are of interest in visual hearing and phonetics. The former pattern 
shows the frequency composition in great detail, so that the individual 
harmonics of voiced sounds may be seen, and the manner in which 
