The New Student's Reference Work/R

R (ǎr), the eighteenth letter, is a voiced consonant. Sometimes it is made between the hard palate (or the teeth) and the tip of the tongue, as in array, rise, trace. This is dental r, employed before a vowel and usually rolled or trilled. Sometimes r is made with the upper surface of the tongue on the back of the hard palate. This is palatal r, as in arm, raw, war. Sometimes r also is a semi-vowel, sometimes a liquid. R is closely related to such mixed vowels as u in up and urn and e in fern. The Scotch and Irish roll r strongly, but the Chinese cannot even say it, substituting l.