1. Tongue Height: This refers to how high or low the tongue is in the mouth.

• High Vowels: The tongue is raised towards the roof of the mouth (e.g., /i/ as in "fleece", /u/ as in "goose").
• Mid Vowels: The tongue is in an intermediate position (e.g., /e/ as in "dress", /ɔ/ as in "thought").
• Low Vowels: The tongue is lowered in the mouth (e.g., /æ/ as in "trap", /ɑː/ as in "father").

2. Tongue Backness: This refers to how far forward or backward the tongue is in the mouth.

• Front Vowels: The tongue is positioned towards the front of the mouth (e.g., /i/ as in "fleece", /e/ as in "dress").
• Central Vowels: The tongue is in a central position (e.g., /ə/ as in "about", /ɜː/ as in "nurse").
• Back Vowels: The tongue is positioned towards the back of the mouth (e.g., /u/ as in "goose", /ɔ/ as in "thought").

3. Lip Rounding: This refers to whether the lips are rounded or unrounded.

• Rounded Vowels: The lips are rounded during the articulation (e.g., /u/ as in "goose", /ɔ/ as in "thought").
• Unrounded Vowels: The lips are not rounded (e.g., /i/ as in "fleece", /æ/ as in "trap").

4. Tenseness: This refers to the degree of muscle tension in the tongue.

• Tense Vowels: Produced with greater muscle tension and are generally longer (e.g., /i/ as in "fleece", /u/ as in "goose").
• Lax Vowels: Produced with less muscle tension and are generally shorter (e.g., /ɪ/ as in "kit", /ʊ/ as in "foot").

5. Nasality: This refers to whether air escapes through the nose during the articulation.

• Oral Vowels: The velum is raised, blocking airflow through the nose (most English vowels).
• Nasal Vowels: The velum is lowered, allowing air to escape through the nose (common in languages like French).

6. Monophthongs and Diphthongs:

• Monophthongs: Vowels with a single, stable articulation (e.g., /æ/ as in "trap").
• Diphthongs: Vowels that involve a glide from one vowel quality to another within the same syllable (e.g., /aɪ/ as in "price", /ɔɪ/ as in "choice").