ര /ɾ/ (alveolar tap)
റ /r/ (alveolar trill)
ര /ɻ/ (approximant)
But according to Omniglot, ര is a dental trill and റ is an alveolar trill.
Who's right? Or are these both acceptable variants? AIUI in spoken Tamil, there is no difference between the sounds written ர and ற, is it the same in Malayalam? I have some books on learning Malayalam, but they don't help at all.