I cannot offer you an extensive program, but I can tell you this: I teach Japanese students, who usually pronounce both /l/ and /r/ as /l/. I need to do 2 things with them: (1) make their /l/ more distinctive by clipping the hard palate with their tongue tips more clearly (because they will be distinguishing two similar liquid sounds that they currently pronounce alike) and (2) have them push their tongues away from their teeth with their ballpoint pens while they are pronouncing /r/ words.
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