The term articulation refers to the bio-mechanical process of altering the flow of air through the vocal tract to produce sounds.
Sounds are described not by how they sound to the ear, but rather how they are produced in the vocal tract. In the posts below dealing with the different sounds in English, they are so named, and each sound is described based on how the vocal organs interact with each other in producing each specific sound. In fact, the word articulate actually means move. Sounds are produced my moving the articulators (things that can be moved) within the vocal tract (lips, tongue, etc). Terminology relating to the vocal organs, articulators, and points of articulation is defined below. Click the head diagram to the right for an interactive map showing the locations and shapes discussed.
Alveolar refers to the alveolar ridge (purple in diagram), which is flat area just behind the front upper teeth but before the edge of the roof of the mouth. When pronouncing these sounds the tongue touches (/t/, /d/, /n/), or nearly touches (/s/, /z/) the alveolar ridge.
Dental refers to the teeth, particularly the front upper teeth. The tongue touches these teeth when producing the sounds (/θ/as in three, and /ð/ as in there). These teeth touch the bottom lip when producing /f/as in fair and /v/as in very.
Glottal refers to sounds in which the airway is constricted by tightening the airway in the back of the throat. The primary glottal sounds in English are /h/ as in happy, and the vowels.
labial refers to the lips. Sounds produced with the lips include /f/as in fair and /v/as in very, in which the bottom lip touches the upper front teeth; /b/ as in boy and /p/ as in pop, in which both lips are pressed together to interrupt the airflow; and /m/ as in my, in which the lips come together to fully blow the airflow, directing it instead out through the nose.
Lengual refers to the tongue. Most consonants are produced by touching the tongue to another part of the mouth. Vowels are formed by changing the shape of the tongue within the mouth (it’s really a big muscle).
Nasal refers to the nose. Three sounds /m/ as in mom, /n/ as in nice, and /ŋ/ as in ring are nasal, meaning that the flow of air out of the body passes through the nose rather than through the mouth.
Palatal refers to the roof of the mouth (flat purple area in the diagram) behind the alveolar ridge but in front of the velum (see below). The tongue touches the palate in producing the sounds /∫/ as in shoe, /ʒ/ as in pleasure, /t∫/ as in church, /dʒ/ as in jelly. It almost touches the palate in /r/ as in read and /ɝ/ as in dinner.
Velar refers to the velum (green in the diagram) which is the soft portion of the roof of the mouth at the very rear of the mouth. It is generally the farthest point the tongue can reach by curling backward. Velar sounds are produced when the rear portion of the tongue is brought near the velum (/w/ as in wait), or contacts the velum (/k/ as in cat and /g/ as in good).