People with Asperger have problems with language in a social setting.

• It may be difficult to choose a topic of conversation, their body language may be off, and it may be difficult for them to recognize that the other person has lost interest in the topic.
• They may speak in a monotone, and may not respond to other people's comments or emotions.
• They may have difficulty understanding sarcasm or humor.

Other symptoms may include:

• Problems with eye contact, facial expressions, body postures, or gestures (nonverbal communication)
• Singled out by other children as "weird" or "strange"
• Difficulty developing relationships with children their own age
• Inability to respond emotionally in normal social interactions
• Not flexible about routines or rituals
• Lack of showing, bringing, or pointing out objects of interest to other people
• Do not express pleasure at other people's happiness
• Preoccupied with parts of whole objects
• Repetitive behaviors, including repetitive behavior that injures themselves
• Repetitive finger flapping, twisting, or whole body movements
• Unusually intense preoccupation with narrow areas of interest, such as obsession with train schedules, phone books, or collections of objects

Physical, emotional, and mental tests are usually done to rule out other causes.