Stammering .. is an acquired behaviour not inherited.WRONG. Stuttering runs in families, and about half is due to genes. Moreover, gene mutations have been located, most members in some families are stuttering, and monozygotic twins are more likely to stutter than dizygotic twins.
Here are some of the many causes according to Bagchi.
Some of the causes that lead to the development of stammering are :
1. Childish imitation of other stammerers either in the family or outside;As always, millions have experienced one of these "causes" but none stutters. And millions stutter than have not experienced many of these "causes".
2. An after effect of certain serious illness such as typhoid, malaria, prolonged fever, convulsion etc;
3. Feeling of insecurity in the early age of school;
4. Strict, rude & rough guardianship;
5. Sudden physical or mental shock;
6. Shy or introvert nature from childhood;
7. Very fast speaking habit;
8. Mal-adjustment between parents;
9. Disturbances and quarrel in the family;
10. If the thought process is very fast;
11. Lack of co-ordination between thinking & speaking;
12. Stiff competition in all spheres of life;
13. If one is multilingual;
14. Side effects of strong medicinal action specially allopathy medicine;
15. Subjected to tremendous fear and tension from childhood;
16. If the child is left alone for some time without parents or familiar people;
17. When a second child is born in the family;
18. Seeing some horrifying scenes in real life or in movies;
19. If the child is weak or sickly;
20. When pressurised by parents to achieve difficult and high targets;
21. When forcibly changed from left handed behaviour to right-handed;
22. The child tries to attract attention and stammers when neglected;
23. If the teacher is strict and always punishes and terrorizes the child;
24. Humiliation in front of friends and class mates;
25. If one is frightened of every little thing;
26. Hurting one's head due to some accident, specially the back side of the head and
27. If parents and family members all talk very fast, the child is unable to compete with their speed and thus faulters.
India, watch out for his expertise!!!
Note: I am not saying that some of his advice might not be useful, but I am only referring to his understanding of stuttering in the light of scientific research.