Japanese speakers
Mistake: Pronouncing every letter as "TERU HIMU" with a full h and a katakana i vowel, or as "TERU IMU" dropping the h but with clear syllable breaks.
Why: Katakana English inserts vowels between consonants and treats each word as separated.
Fix: The h of "him" is elided in fast speech, and the l of "tell" links directly to the i of "him": [ˈtɛlɪm]. Say "tellim" as one word.
Korean speakers
Mistake: Preserving a clear [h] onset for "him", producing "TEL HIM" with a visible break between the words.
Why: Korean does not commonly elide word-initial [h], and orthography-based learning reinforces its presence.
Fix: In casual English, the [h] of unstressed pronouns ("him", "her", "his", "he") is very often dropped. "Tell him" becomes [ˈtɛlɪm]. This is standard, not casual — even news anchors do it.
Spanish speakers
Mistake: Producing a strong dark l or a Spanish-style light l in "tell", then keeping the h of "him" audible.
Why: Spanish l is light and doesn't have the darker "velarized" quality English uses at word-final position; and Spanish speakers typically pronounce written h... except they know Spanish h is silent, which can create over-correction on English h.
Fix: English "tell" uses a dark l [ɫ] at the end. Then drop the h of "him" entirely: [ˈtɛɫɪm]. Even easier since Spanish already treats h as silent.