Negative language can act as a barrier to good communication.

It can bring about poor image, defeat and confusion.

It adds a sense of blame and could result in a negative outcome.

If the receiver of the communication takes the negative language personally, they may stop listening or become defensive.

If a person is generally pessimistic, then there is very little motivation to complete a task, and if the pessimistic person is the leader, then the whole group could give up.

• Posture – standing tall with shoulders back.
• Eye contact – solid with a "smiling" face.
• Gestures with hands and arms – purposeful and deliberate.
• Speech – slow and clear.
• Tone of voice – moderate to low.

• how we position our bodies
• our closeness to and the space between us and other people   
• our facial expressions
• our eyes especially and how our eyes move and focus, etc
• how we touch ourselves and others
• how our bodies connect with other non-bodily things, for instance, pens, cigarettes, spectacles and clothing
• our breathing, and other less noticeable physical effects, for example our heartbeat and perspiration
  

Body language tends not to include:

• the pace, pitch, and intonation, volume, variation, pauses, etc., of our voice.
  

- Emphasize description over personal approval

Not having this skill might make you come across as rude or uninteresting.