Age When Deafness Occurred
The vast majority of the deaf lost their hearing in early life, and most of them in the tender years of infancy and childhood. More than ninety per cent (90.6, according to the returns of the census) became deaf before the twentieth year; nearly three-fourths (73.7 per cent) under five; over half (52.4 per cent) under two; and over a third (35.5 per cent) were born deaf. Deafness thus occurs in a strongly diminishing ratio with advancing years.[6] These facts may be indicated by the following table,[7] which shows the percentages of those who became deaf at different ages.
THE DEAF ACCORDING TO AGE OF OCCURRENCE OF DEAFNESS
| At birth | 35.5 |
| After birth and under two | 16.9 |
| Under two years | 52.4 |
| 2 and under 4 | 17.1 |
| 4 and under 6 | 7.3 |
| 6 and under 8 | 4.5 |
| 8 and under 10 | 2.8 |
| 10 and under 12 | 1.8 |
| 12 and under 14 | 1.6 |
| 14 and under 16 | 1.3 |
| 16 and under 18 | 1.0 |
| 18 and under 20 | 0.8 |
| Under five | 73.7 |
| 5 and under 10 | 10.5 |
| 10 and under 15 | 4.0 |
| 15 and under 20 | 2.4 |
| Under 20 | 90.6 |
| 20 and under 40 | 5.7 |
| 40 and under 60 | 2.4 |
| 60 and under 80 | 1.1 |
| 80 and over | 0.2 |
Ability of the Deaf to Speak
We have just seen that "dumbness" frequently follows upon deafness, or that it is usually believed to be an effect of deafness. It is true that with the majority of the deaf phonetic speech is not employed to any large extent; but there is at the same time a fair number who can, and do, use vocal language. This speech varies to a wide degree, in some approximating normal speech, and in others being harsh and understood with difficulty; and it depends in the main upon three conditions: 1. the age at which deafness occurred, this being the most important factor; 2. the extent to which the voice is cultivated; and 3. the remaining power of the ear (which is found but seldom).[8]
Of the deaf persons enumerated in the census,[9] 21.5 per cent were reported able to speak well; 15.8 per cent imperfectly; and 62.7 per cent not at all. In other words, somewhat over a third of the deaf can speak more or less, one-fifth being able to speak well, and one-sixth imperfectly, while over three-fifths do not speak at all. The dependence of the ability to speak upon the age of becoming deaf is clearly in evidence here, the proportion of those not able to speak showing a great decrease with the rise of this age. Thus, of those born deaf, 83.5 per cent cannot speak at all; of those becoming deaf after birth and under five, 74.6 per cent; of those becoming deaf after five and under twenty, 26.5 per cent; and of those becoming deaf after twenty, 3.4 per cent.
Some of the deaf are able to read the lips of the speaker, or as it is better expressed, to read speech, or to understand what is being said by watching the motions of the mouth. This in reality is a distinct art from the ability to speak, though popularly they are often thought to be co-ordinate or complementary one to the other. Like the ability to speak, it varies in wide degree, from the ability to understand simple and easy expressions only, to the ability to follow protracted discourse; and like the ability to speak, it is found in increasing frequency with the rise of the age of becoming deaf. According to the census,[10] 38.6 per cent of the deaf are able to read the lips. Of those born deaf, 28.0 per cent have this ability; of those becoming deaf after birth and under five, 37.1 per cent; of those becoming deaf after five and under twenty, 64.3 per cent; and of those becoming deaf after twenty, 43.6 per cent.[11]