The th in brother is a voiced sound, and the th in three is a voiceless sound. Do you know how to pronounce the th sound? Stick out your tongue between upper teeth and lower teeth, that is, put your tongue between your upper teeth and lower teeth and say th, making the air pass over your tongue. Then you can make the th sound. To make a voiced th, you should vibrate your vocal cord. To make a voiceless th, you don't need to vibrate your vocal cord, though you feel a slight vibration on your vocal cord when you say a voiceless th.
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The sentences above is about how to make the th sound. Would you check them and correct errors?
In the following sentence, I'd delete the underlined section and start the sentence with "Put":
Stick out your tongue between upper teeth and lower teeth, that is, put your tongue between your upper teeth and lower teeth and say th, making the air pass over your tongue.
Otherwise, it reads well.
=)
There is no vibration of the vocal cords on the voiceless "th"
The instructions for pronouncing the "th" sound in the sentences above are accurate and do not contain any errors. The first step is to stick out your tongue between your upper and lower teeth to allow the air to pass over your tongue. This will enable you to make the "th" sound.
To pronounce a voiced "th" sound, you should also vibrate your vocal cords while making the sound. This creates a buzzy or humming sensation in your throat.
On the other hand, for a voiceless "th" sound, you do not need to vibrate your vocal cords. However, you may still feel a slight vibration on your vocal cords when producing a voiceless "th" sound.
Overall, the instructions provided are clear and accurate, describing how to correctly pronounce the "th" sound.