Japanese speakers
Mistake: Pronouncing it as "TEN KAPPUSU" with clear [n] and aspirated katakana-style consonants.
Why: Katakana English preserves each word as separate.
Fix: The n of "ten" assimilates to [ŋ] before the velar k of "cups": [ˈtɛŋˈkʌps]. Say "tengcups" as one unit.
Korean speakers
Mistake: Producing clear [n] and aspirated [kʰ] with syllable break.
Why: Korean prosody keeps consonants clean.
Fix: n → [ŋ] before /k/ in casual speech: [ˈtɛŋˈkʌps]. Same rule as "in case" [ˈɪŋˈkeɪs], "green car" [ˈɡriːŋˈkɑːr].
Spanish speakers
Mistake: Producing clear [n] without assimilation, and clean [k] with light release.
Why: Spanish n has partial assimilation but less systematic than English.
Fix: English n before k systematically becomes velar [ŋ]: [ˈtɛŋˈkʌps]. Universal in fluent speech.