The science of soft consonants

I am returning to a topic I wrote about five years ago. We make sounds in different ways and those sounds, primarily, vowels, hard consonants, and soft consonants are formed and come out of our throats and mouths with different frequency and force. The soft consonants are particularly important in understanding what words actually are. As I begin, I will quote from myself and the article I wrote in June of 2015.

“Sound energy travels in waves that are invisible and is measured in frequency and amplitude. I will define both of these words.

Frequency is measured in the number of sound vibrations in one second. That measurement is tested by a machine called an audiometer and the scores recorded on a graph called an audiogram. The machine makes preprogrammed sounds at certain frequencies, pitches, or tones. The slower the vibration per second the lower the tone and the faster the vibrations per second the higher the tone.

The cycle per second is called a “Hertz.” A healthy ear can hear sounds of very low frequency, 20 Hertz (or 20 cycles per second), to a very high frequency of 20,000 Hertz. The lowest A key on the piano is 27 Hertz. The middle C key on a piano creates a 262 Hertz tone. The highest key on the piano is 4186 Hertz. Men typically speak in a range from 1800-2800 Hertz and women and children from 3000 to 4200 Hertz.

This is because women and children have shorter and thinner vocal cords than men. The effect is just like piano strings in tone difference. Many patients with high frequency hearing loss will tell me they have greater difficulty hearing women’s voices and are missing a great deal of what their grandchildren are saying.

Amplitude measures how forceful the wave is. There are a number of scientific factors in sound amplitude or force, but we perceive it as loudness or volume. It is measured in decibels or the abbreviation dBA of sound pressure. 0 dBA is the softest level that a person can hear. Normal speaking voices are around 65 dBA. A household vacuum runs at about 80 dBA, a rock concert can be about 120 dBA, a jet plane taking off at 150 dBA, and a hunting rifle discharges at 165 dBA. Sounds that are 85 dBA or above can permanently damage your ears. The more sound pressure a sound has, the less time it takes to cause damage. For example, a sound at 85 dBA may take as long at 8 hours to cause permanent damage, while a sound at 100 dBA can start damaging hair cells of the inner ear after only 30 minutes of listening.”

The vowels resonate through the larynx and are suppressed somewhat into the lowers frequencies. Hard consonants like, K, B, and P have a vowel sound embedded in them and tend to move into middle frequencies. The soft consonants like S, F, Ha, and TH blends float in the higher frequencies. They have no involvement with vowels, do not pass through the larynx, take less time to pronounce, and have less energy behind them.

Soft consonants are pronounced at higher frequencies, have less energy, and less time duration so when a person has typical high frequency hearing loss, these vitally important speech understanding clues drop out. Patients who experience this generally tell me, “I can hear people talking, but I can’t clearly understand what they are saying. That is because high frequency hearing loss takes away the part of speech that helps us sort out what is actually being said. I know that I am simplifying a large topic in the area of speech pathology. There is much more that could be said but, let me demonstrate what I am saying visually with some capital letters in a phrase that takes out these clues. Without your soft consonants IT I ARD TO EAR AT PEOPLE ARE AYING.

Sound perception ability, or a hearing test measures the frequencies (cycles per second) and the amplitude (force) of the sound wave the person can sense at a threshold levels and thereby the professional produces a graph that shows ability to hear and or the inability to hear soft consonants and other important speech sounds.

If you have the symptoms of hearing loss let a professional help you find out why. The hearing professional will help you sort out the technology level to meet your need, your budget, and answer your hearing need questions.


Jeffrey L. Bayliff, NBC-HIS is the owner of Hear the Birds Hearing Aid Center, Lock Haven, PA


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