false. i believe that the environment a person grows up in would determine their tone of voice, or perhaps how they speak to others and present themselves. for example: a boy grows up in a strict, verbally aggressive household, then he would be more likely to have a stern or serious tone of voice. but if the boy grows up in a "gentle parenting" household, he would be more likely to have a pleasant, calmer, more cheerful voice. the depth of your voice does not always determine whether you speak stern and serious or pleasant and cheerful.