In casual American English, "Is his name Jon or John?" sounds like "ihz hihz NAYM JAHN er JAHN". Three things happen here, and the headline one is the Consonant-to-Vowel Linking: the consonant links forward into the next vowel without a pause. Keep stressed words long, unstressed words short, and link the consonants forward into the vowels.
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Read the sentence out loud at native speed. The mic stays on your device — nothing's uploaded.
What makes this sentence sound American.
The "" at the end of "is" flows directly into the vowel starting "his" — the consonant migrates to the next word with no pause between. This is called the Consonant-to-Vowel Linking, how Americans glue words together so they sound like one phrase. It comes out as ihz.
What's happening in this sentence.
Small tricks that turn a textbook sentence into how an American actually says it.
Common pronunciation mistakes in American English.
The textbook way isn't wrong — it's just not how anyone actually says it.
Pausing between the words.
The "" at the end of "" flows directly into the vowel starting "" — the consonant migrates to the next word with no pause between. Final consonant "migrates" to next word — no pause between.
Pronouncing the function word too fully.
"is" is a function word — in connected speech, the full vowel reduces to a quick "" sound and consonants may simplify. Full vowel reduces to schwa /ə/ or other weak vowel. Consonants may simplify.
Pronouncing the H clearly.
The "h" in "his" is dropped in connected speech — the preceding word's final consonant links directly to the remaining vowel — most natural in casual, rapid speech; in careful or formal speech, the H is typically kept. /h/ is dropped entirely — preceding word links directly into the remaining vowel (works after both consonants and vowels).