Pragmatics

Social Language Use (Pragmatics) 
You have invited your friend over for dinner. Your child sees your friend reach for some cookies and says, "Better not take those, or you"ll get even bigger." You're embarrassed that your child could speak so rudely. However, you should consider that your child may/may not know how to use language appropriately in social situations and did not mean harm by the comment.
An individual may say words clearly and use long, complex sentences with correct grammar, but still have a communication problem - if he or she has not mastered the rules for social language known as pragmatics. Adults may also have difficulty with pragmatics, for example, as a result of a brain injury or stroke.

Pragmatics involve three major communication skills:
Using language for different purposes, such as
     greeting (e.g., hello, goodbye)
     informing (e.g., I'm going to get a cookie)
     demanding (e.g., Give me a cookie)
     promising (e.g., I'm going to get you a cookie)
     requesting (e.g., I would like a cookie, please)

 Changing language according to the needs of a listener or situation, such as
     talking differently to a baby that to an adult
     giving background information to an unfamiliar listener
     speaking differently in a classroom than on a playground

Following rules for conversations and storytelling, such as 
     taking turns in conversation
     introducing topics of conversation
     staying on topic
      rephrasing when misunderstood
     how to use verbal and nonverbal signals
     how close to stand to someone when speaking
     how to use facial expressions and eye contact

These rules may vary across cultures and within cultures. It is important to understand the rules of your communication partner.

An individual with pragmatic problems may:
   say inappropriate or unrelated things during conversations
   tell stories in a disorganized way
   have little variety in language use

It is not unusual for children to have pragmatic problems in only a few situations. However, if problems in social language use occur often and seem inappropriate considering the child's age, a pragmatic disorder may exist. Pragmatic problems often coexist with other language problems such as vocabulary development or grammar. Pragmatic problems can lower social acceptance. Peers may avoid having conversations with an individual with a pragmatic disorder.