If the person find it hard to speak or interact freely especially in lectures or when speaking to high-class people and he is normal when dealing with his family is this what they called social phobia?

Could Be: I think it could be considered a phobia, but i think you're being a little hard on yourself. With experience and confidence, the feelings of nervousness could likely diminish. Some people find it harder to speak to groups of people at first but with time can excel at this type of interaction. Keep doing your best and i suspect you'll improve with time.

Social anxiety : Social anxiety disorder (sad), also known as social phobia, is a common disorder characterized by excessive fears of scrutiny, embarrassment and humiliation in social or performance situations, leading to significant distress or impairment in functioning. The disorder has two subtypes: generalized and nongeneralized sad. In generalized sad, distressing fears are experienced in most social situat.

A form of it: Fear of humiliation in public is the core abnormal, distressing mental feature of social phobia. For you it is provoked in formal settings, but not with family members by whom you know you are accepted and loved.

Yes Social Phobia: See this pg anxiety disorders assn of bc which contains educational & self-help tools (incl a video) for managing & even overcoming social phobia/anxiety: http://www.Anxietybc.Com/resources/social.Php effective treatment for social anxiety will involve putting yourself in feared social situations, going from ones you fear only a little to others you fear a lot. A cbt expert coach can be big help!