When a child grows up to be a teenager or a junior high school student, he or she often becomes hoarse. Parents and children themselves may think that it is “fire” or throat inflammation, but in fact, it may be that the child has entered the voice change period. So, what is the “voice change period”? The larynx and vocal cords are very tender and fragile from the time of birth until the age of 10-14. The structure and development of the larynx are similar for boys and girls, so there is no difference between the voices of boys and girls at this stage, and they all belong to the “child voice”. But puberty (boys at about 12-15 years old, girls at 11-14 years old) due to significant changes in the level of hormones in the endocrine system, the larynx body in a short period of time rapidly increased, especially the male puberty larynx in terms of size, shape and physiological function are obvious changes, this period is called the voice change period. I. The performance of the vocal change period voice becomes split, sandy, boring, some overnight suddenly become hoarse, can not send high notes, or in the same time speech on several tones to. The length of time for voice recovery also varies. Generally, it takes 3 to 6 months for the voice to recover gradually. In some cases, it takes 1 to 2 years or more for the voice to mature and slowly change over after a long period of hoarseness. After the voice change period, both boys and girls have different degrees of voice changes, and girls gradually become adult women with a clear voice. Boys’ voices change more dramatically, with low pronunciation and a broad chest voice. Voice protection during the voice change period 1.Ensure sufficient sleep time; 2.Don’t shout or yell in a strange voice during the voice change period, and try to speak as little as possible. 3. Don’t consume stimulating things, such as wine, chili, garlic and smoking. Also do not eat too much crunchy food, such as fried food. Drink more warm water and less drinks. 4.Keep your throat and mouth clean and hygienic, brush your teeth every day, rinse your mouth after meals, pay attention to adding and subtracting clothes with climate change, and pay attention to sleeping with covers at night to prevent colds. 5.Strengthen physical exercise, ensure a nutritious diet, it is advisable to choose foods rich in vitamin B and C, and eat more fruits and vegetables. 6, psychological and emotional impact on the smooth passage of the voice change period also has a great impact, so to maintain a normal psychological state, calm and stable emotions, the correct view of voice change, to avoid the emergence of “male voice female tone” and other abnormal voice.