1. Obstruction of Airflow: Consonants are produced by partially or completely obstructing the airflow from the lungs through the vocal tract. This obstruction can be made by:
* The tongue: Touching the roof of the mouth (alveolar ridge, hard palate, soft palate), teeth, or lips.
* The lips: Closing or nearly closing the lips.
* The vocal folds: Closing the vocal folds to create a "stop" (like in "p," "b," or "t").
2. Manner of Articulation: How the airflow is obstructed determines the manner of articulation:
* Stops: Complete closure of the vocal tract, then a sudden release (e.g., "p," "b," "t," "d," "k," "g").
* Fricatives: Narrowing of the vocal tract, creating friction (e.g., "f," "v," "s," "z," "th" in "thin" and "this").
* Affricates: Begin as a stop, then release as a fricative (e.g., "ch" in "chair," "j" in "jump").
* Nasals: Air flows through the nose (e.g., "m," "n," "ng" in "sing").
* Liquids: Liquids have a slightly more open passage for air than stops, but with some obstruction, resulting in a "liquid" sound (e.g., "l," "r").
* Approximants: Minimal obstruction, more like a vowel (e.g., "w," "y").
3. Place of Articulation: Where the airflow is obstructed determines the place of articulation:
* Bilabial: Both lips (e.g., "p," "b," "m").
* Labiodental: Lower lip against upper teeth (e.g., "f," "v").
* Dental: Tongue against upper teeth (e.g., "th" in "thin," "th" in "this").
* Alveolar: Tongue against alveolar ridge (e.g., "t," "d," "s," "z," "n," "l").
* Post-alveolar: Tongue behind the alveolar ridge (e.g., "sh" in "ship," "zh" in "vision").
* Palatal: Tongue against hard palate (e.g., "y," "j" in "jump").
* Velar: Tongue against soft palate (e.g., "k," "g," "ng" in "sing").
* Glottal: Vocal folds (e.g., "h").
4. Voicing: Whether or not the vocal folds vibrate during consonant production:
* Voiced: Vocal folds vibrate (e.g., "b," "d," "g," "v," "z").
* Voiceless: Vocal folds do not vibrate (e.g., "p," "t," "k," "f," "s").
It's important to note that these criteria can be complex and nuanced, and there are exceptions to these general rules. However, these criteria provide a basic framework for understanding the characteristics of consonants in language.