This year, my seminar in phonology deals with intonation in English. Every student in the class reads aloud example sentences for intonation training in the text book.
At my turn, I noticed myself imaging how my Canadian friend I lived with would pronounce the passage.
I had a déjà vu feeling doing that. And...aha! It is when I try to talk in the standard (Kanto) style of intonation. (I'm a Kansai dialect speaker.) I always imagine how my Tokyo pal would speak and imitate his virtual speech played in my mind.
If other people also do as I do when they try to speak in a dialect or a language with a intonation pattern different from theirs, then having a one person to imitate will be a big help for intonation practice.
And I believe it will be superior to listening to learning materials in that you can have a concrete image of the person you know, although it may be insufficient for providing a variety of speech patterns.