Japanese speakers
Mistake: Pronouncing each word fully as "NOTTO ATTO OORU" with three separated words and hard t's.
Why: Katakana English preserves each syllable; the flap-t compression is unfamiliar.
Fix: Both t's flap between vowels: [ˈnɒɾəˈɾɔːl]. Say "nada dall" — three words compressed into two beats. The [t] sounds like a soft d.
Korean speakers
Mistake: Producing aspirated [tʰ] on both t's and clear syllable boundaries.
Why: Korean ㅌ carries aspiration.
Fix: The American flap-t (short d-like tap) fires between vowels: [ˈnɒɾəˈɾɔːl]. In RP the t's may stay as [t] but the linking is still continuous.
Spanish speakers
Mistake: Producing full Spanish [ɾ] taps or preserving each word separately.
Why: Spanish [ɾ] is longer than English flap-t.
Fix: Keep the flaps very light: [ˈnɒɾəˈɾɔːl]. And treat the whole phrase as one compressed unit — three words, two beats.