Common mistakes by native language
Japanese speakers
Mistake: Pronouncing it as "RETTO YU" with a hard t and separated syllables.
Why: Katakana English preserves the t and blocks the t+y coalescence.
Fix: The t of "let" and the y of "you" merge into [tʃ], and "you" reduces to schwa: [ˈlɛtʃə]. Written informally as "letcha".
Korean speakers
Mistake: Producing an aspirated [t] and full [ju:] vowel.
Why: Korean maintains careful articulation.
Fix: Merge t + y to [tʃ]: [ˈlɛtʃə]. Same rule as "get you → getcha", "got you → gotcha".
Spanish speakers
Mistake: Producing separate [t] + [j], or overshooting to a full Spanish ⟨ch⟩.
Why: Spanish [j] resists coalescence; Spanish [tʃ] is more energetic.
Fix: Soft merged [tʃ]: [ˈlɛtʃə]. Quick and light.
Notes
"Let you" fuses to [ˈlɛtʃə] via the same voiceless t+y coalescence as "get you", "got you", "meet you", "bet you". The verb "let" is one of English's most flexible causative verbs, and "let you" appears in a huge range of contexts: giving permission ("let you in"), communication commitment ("let you know"), preventing disappointment ("won't let you down"), offering leniency ("let you off"). All share the same phonology [ˈlɛtʃə]. In fast speech, the [tʃ] may soften further to a barely-audible [ʃ], but the coalescence is always present — never separate [t] + [j]. Mastering this pattern instantly makes a large family of "let + pronoun" phrases sound natural: "let him know" [ˈlɛtɪm ˈnoʊ], "let her go" [ˈlɛtər ˈɡoʊ], "let us try" (formal) or "let's try" (casual).