As I am Korean, I also feels same difficulty for English sound between 'r' and 'l'. 'f' and 'p'. because in Korean, 'r' and 'l' have same sound 'ㄹ'
The Korean consonantal distinctions are particular tricky, though, because it’s one consonant in English being not two sounds in Korean but three.
e.g. Moving through a couple cultures... r->l->n and b->p->f or b->v->w might turn "rollerblade" into "lolaweulad"
###