What do you mean, "Czech does not have /r/"?
This is my all-time favorite question at a conference. It was posed at an LSA (Linguistic Society of America) meeting
in LA in 1979. The question shows the juncture of phonetics, phonology, culture, and inquiry. In order to appreciate the irony, you have to imagine a consternated colleague posing this question in her native Czech accent. If a native speaker says she has an /r/, then who is a speaker of another language to question that unless he wishes to create his own /r/* definition?
But, of course, the previous presenter had said, "Czech does not have the [r] sound." If you understand the distinction between phonetics and phonemics, then you will be able to see how correctly transcribing these contentious queries resolves the apparent disagreement. It will also help you if you have a grasp of how the definite article in English works.
Some links to [r] production in English: