TL;DR: The idea that people born in certain months (September, October, November, December) are easier to get along with is based on astrology and zodiac signs. Each zodiac sign is associated with specific personality traits, but astrology is not scientifically proven. While some people may find similarities among individuals born in the same month, compatibility depends on various factors beyond birth month such as shared interests and values. Claims of determining someone's birth month by their voice are unlikely to be accurate and should be taken with skepticism.