R is the eighteenth letter of the English Alphabet, and an articulation sui generis, having little or no resemblance in pronunciation to any other letter. But from the position of the tongue in uttering it, it is commutable with l, into which letter it is changed in many words by the Spaniards and Portuguese, and some other nations; as l is also changed into r. It is numbered among the liquids and semi-vowels, and is sometimes called the canine letter. It is uttered with a guttural extrusion of the breath, and in some words, particularly at the end or after a labial and a dental letter, with a sort of quivering motion or slight jar of the tongue. Its English uses, which are uniform, may be understood by the customary pronunciation of rod, room, rose, bar, bare, barren, disturb, catarrh, free, brad, pride, drip, drag, drown.

In words which we have received from the Greek language, we follow the Latins, who wrote h after r, as the representative of the aspirated sound with which this letter was pronounced by the Greeks. It is the same in the Welsh language. But as the letter is not aspirated in English, h is entirely superfluous; rhapsody, rheum, rhetoric, being pronounced rapsody, reum, retoric.

As an abbreviation, R. in English, stands for rex, king, as George R.

As a numeral, R, in Roman authors, stands for 80, and with a dash over it, for 80,000. But in Greek, with a small mark over it, signifies 100, and with the same mark under it, it denoted 1000x100, or 100,000. In Hebrew, denoted 200, and with two horizontal points over it, 1000x200, or 200,000.

Among physicians, R. stands for recipe, take.