I have recently started to notice how deaf a lot of adult Thais are, every time they are blocking my way and I have to get past I have to shout at them, when before a pleasant excuse me "in Thai" would be enough.
I have to believe it is because of their addiction to noise, these very loud bass sounds at social gatherings, weddings, funerals etc which Thais attend.
There must be lots of babies and children affected all the time they are growing up and will have hearing problems, maybe that's why they are always shouting at each other.