You have a hard time understanding and communicating with normal people; you are either too strange, too animalistic, too bestial or too stupid to understand human speech and behavior. Sorcerers with Summoning can speak to you, as can other creatures of a similiar background - you can speak to others of your kind, but if 'your kind' is common in the campaign, this is not really a flaw at all. Some communication schticks may work, but never perfectly. Otherwise you are entirely incommunicado.