What it is: the student speaks along with a native voice, about a quarter of a second behind, copying its melody, stress and rhythm rather than every single word.
Why it works: a quarter of a second leaves no time to translate. Sound goes straight from ear to mouth, and the student's timing locks onto the rhythm of the sentence. In one study, nine shadowing lessons improved how well learners heard the individual sounds of English.
Hamada, Language Teaching Research, 2016 The Science of Shadowing



