Open Back Vowel Distinction: /ɑ/ versus /æ/

Example: 'cot' [kɑt] vs. 'cat' [kæt]

The lips are completely neutral for /ɑ/.
For /æ/, the mouth stretches laterally as the corners retract.

Low Back vs. Central Vowels: /ɑ/ versus /ʌ/

Example: 'hop' [hɑp] vs. 'cup' [kʌp]

Significant jaw drop is required for /ɑ/.
For /ʌ/, the jaw is higher, and the tongue rests centrally.

Front Unrounded Comparison: /æ/ versus /ɛ/

Example: 'map' [mæp] vs. 'met' [mɛt]

The /æ/ sound utilizes the maximum jaw opening for front vowels.
Transition to /ɛ/ involves raising the jaw slightly with less lip tension.

Back Unrounded vs. Rounded: /ɑ/ versus /ɔ/

Example: 'stock' [stɑk] vs. 'stalk' [stɔk]

Lips remain relaxed and open for /ɑ/.
The /ɔ/ sound necessitates a slight protrusion and rounding of the lips.

Tense vs. Lax High Front: /i/ versus /ɪ/

Example: 'beat' [bit] vs. 'bit' [bɪt]

The tongue arches high near the palate for /i/.
For /ɪ/, the jaw drops more, and the tongue is slightly lower and laxer.

Lax Front Vowels: /ɪ/ versus /ɛ/

Example: 'fit' [fɪt] vs. 'bet' [bɛt]

The /ɛ/ vowel has a lower jaw position than /ɪ/.
In /ɪ/, the tongue body is closer to the roof of the mouth.

Monophthong vs. Diphthong Onset: /i/ versus /eɪ/

Example: 'see' [si] vs. 'say' [seɪ]

The jaw remains relatively closed for the steady /i/ sound.
The /eɪ/ diphthong begins with a wider jaw opening before gliding up.

Diphthong Glide vs. Lax Vowel: /eɪ/ versus /ɪ/

Example: 'lake' [leɪk] vs. 'lick' [lɪk]

The initial sound of /eɪ/ drops the jaw significantly.
The tongue is forward for both, but /ɪ/ is static and lower than the /eɪ/ target.

Diphthong Onset vs. Mid Vowel: /eɪ/ versus /ɛ/

Example: 'gate' [geɪt] vs. 'get' [gɛt]

The mouth shape for the /ɛ/ in 'get' matches the start of /eɪ/.
However, the /eɪ/ glide ends with less jaw drop and lip rounding.

Central vs. R-Colored: /ʌ/ versus /ɝ/

Example: 'duck' [dʌk] vs. 'dirk' [dɝk]

The /ʌ/ sound requires total relaxation of lips and cheeks.
For /ɝ/, the lips flare, and the tongue root retracts to produce r-coloring.

Stressed vs. Unstressed Schwa: /ʌ/ versus /ə/

Example: 'cup' [kʌp] vs. 'supply' [səˈplaɪ]

Greater jaw drop characterizes the stressed /ʌ/.
The unstressed schwa /ə/ is central, extremely brief, and involves minimal jaw movement.

Back Rounded Vowels: /ʊ/ versus /u/

Example: 'look' [lʊk] vs. 'Luke' [luk]

Intense lip rounding occurs for the /u/ vowel.
The /ʊ/ sound involves slight flaring but significantly less tension.

Distinguishing Back Vowel Qualities: /ʊ/ versus /ʌ/

Example: 'full' [fʊl] vs. 'fun' [fʌn]

Lips are slightly rounded for the /ʊ/ sound.
The /ʌ/ sound is produced with a completely relaxed, unrounded mouth.

Diphthong vs. High Back: /oʊ/ versus /u/

Example: 'boat' [boʊt] vs. 'boot' [but]

The /oʊ/ diphthong starts with an open jaw and closes to a tight circle.
The pure /u/ vowel maintains the tight circle and high tongue position throughout.

Diphthong vs. Open Back: /oʊ/ versus /ɑ/

Example: 'go' [goʊ] vs. 'got' [gɑt]

The /oʊ/ onset resembles /ɑ/, but the tongue is retracted and higher.
Crucially, /oʊ/ transitions into a rounded position, while /ɑ/ stays relaxed.

Diphthong Contrast: /aʊ/ versus /ɔ/

Example: 'cow' [kaʊ] vs. 'call' [kɔl]

The /aʊ/ diphthong starts with lips pulled back (retracted corners).
The /ɔ/ vowel maintains consistent lip flaring. The /aʊ/ glide ends with less jaw drop.