Japanese speakers
Mistake: Producing "WUDDO YU" with the l pronounced, or as "WOU-RUDO YU" with a full u vowel after d.
Why: The silent l in "would" is counterintuitive from spelling, and Japanese phonotactics resist a bare d before a y consonant.
Fix: Ignore the l — it is completely silent. Fuse the d and y into a single [dʒ] and reduce "you" to [ə]: [ˈwʊdʒə].
Korean speakers
Mistake: Preserving the full [u:] vowel in "you" and articulating a clear [j] onset, giving "WU-DEU YU".
Why: Korean strongly maintains vowel length and clean syllable onsets, especially in polite forms — and "would you" is often used in polite requests.
Fix: In polite English speech the phrase compresses even more, not less. "Would you" becomes [ˈwʊdʒə], with "you" reduced to a schwa. The politeness comes from intonation, not from articulating each sound.
Chinese speakers
Mistake: Adding a small vowel between "would" and "you", or pronouncing d + y as two very separate consonants.
Why: Mandarin does not have the [dʒ] affricate as a coalescence result; Chinese ⟨j⟩ [tɕ] is palatal but articulated differently.
Fix: The [dʒ] you want is the same as English "judge" or the j in "Jack". Practice "judge" first, then insert it in place of the d + y in "would you".