Hi,thank you for posting your query on health care magic. The cause of Puberphonia is as follows: During puberty in males the mass and length of the vocal fold increase and the pitch decrease. Few of the people although having the appropriate vocal fold mass and length after the puberty, but they are not able to switch to the new low pitch voice (male like).Mostly its reason can be usually long time habits from childhood, speaking into a high pitch voice. In this case only thin edges of vocal cords vibrates and also the whole length of the vocal cord does not vibrate. Puberphonia can be very easily treated by speech therapy (vocal exercises) in most of the cases. Duration mostly can be about 1-2 week .Sometimes may take more time. It would be advisable to consult a Speech therapist. Hope this answers your question.Take care.