sentence: society is still highly tribal , with the old seyyid aristocracy , descended from the prophet muhammad , traditionally educated and strict in their islamic observance and highly respected in religious and secular affairs hadhrami diaspora since the early 19th century , large-scale hadhramaut migration has established sizable hadhrami minorities all around the indian ocean , in south asia , southeast asia and east africa including hyderabad , bhatkal , gangolli , malabar , sylhet , java , sumatra , malacca and singapore .