Definition and Negative Connotation of Mouth Breathing
- The term 'mouth-breather' initially referred to children who breathed through their mouths due to a medical condition.
- Over time, it developed a pejorative connotation, defining a stupid person.
- Currently, 'mouth breather' is a pejorative noun with a negative connotation.

Causes and Types of Inability for Nasal Breathing
- Humans are designed to breathe through their noses from birth.
- Infants can only use their noses to breathe in the first six to twelve months, except when crying.
- Chronic mouth breathing can impact health and is classified into obstructive, habitual, and anatomic types.
- Nasal breathing produces nitric oxide, while mouth breathing does not.

Effects of Mouth Breathing on Health
- Mouth breathing is associated with various conditions such as snoring, dry mouth, hoarse voice, bad breath, fatigue, sleep apnea, cheilitis glandularis, Down syndrome, anterior open bite, tongue thrusting habit, cerebral palsy, and ADHD.
- It can lead to gingivitis, gingival enlargement, and increased dental plaque.
- Mouth breathing in children may affect dental and facial growth, potentially leading to a long, narrow face.
- A long, thin face type may predispose individuals to nasal obstruction and mouth breathing.

Additional Approaches to Mouth Breathing
- Native American communities preferred nose breathing and had straight teeth.
- Yogis advocate nose breathing in yoga practice.
- Mouth taping, the practice of keeping the lips shut with surgical tape during sleep, is suggested to prevent mouth breathing.
- The health effects of mouth taping have been little researched.

Mouth Breathing in Non-Human Animals
- Mouth breathing is not the primary mode of breathing in non-human animals.
- Lambs only resort to mouth breathing when their nasal passages are completely obstructed, leading to hypoxemia.