One of the voice’s worst enemies is noise (It’s comes after smoking). When the ear-monitors hear noise, they tell the brain that it will have to “gear-up” and push the voice equipment to over-ride the noise. Noise is annoying when it competes with our important message, so we tend to sub-consciously tense our throat muscles, apply valving forces and push to get the message out. If we talk in noisy areas often, the unconscious brain may ignore the interference to the point that we are not even aware we are straining our voices.
Here are some common sources of speech-competing noises: people talking, yelling or singing; people moving around; people playing musical instruments or with noisy toys; traffic or engine noises (cars, buses, airplanes, trains); office equipment; power tools; heating/air-conditioning systems; house-hold appliances (dishwasher, TV…).