R (letter)
R is rather weak in most varieties of English (compare the trilled r’s of Spanish and Italian or the guttural r’s of French and German, and the two r sounds of Portuguese: it resembles single, medial and final Portuguese r, never double or initial guttural) is pronounced in the front of the mouth (but not so far as Japanese r: the tongue doesn’t go quite so near the teeth): réd, rêal, rîce, wrîte read = rîght, correct, side, rún, árrow, írritate, érror, cárry, bárrier, wróng, rāther.
But it is silent in BrE, before another consonant, although significantly affecting the pronunciation of the preceding vowel (this is sometimes rather confusingly called ‘post-vocalic’ r: pre-consonantal would be more exact): hàrd, vërse, fïrm, wörd, bŏrn, bürn, heàrt, hëard, cürl, nŏrth, wörk, bïrd, përson, làrge, wård, and in îron metal, which in BrE = îon electron.
It can occur before any consonant, although it is rare before j: përjury, màrjoram, Màrjorie.
As in AmE áfterwards, r before consonants is not silent in General American, Scottish, Irish and many other varieties of English, where, in every example given above, the r is distinctly heard.
r is very often doubled in the middle of words, especially after á, é and ú and before ôw and y, giving the short sound of the preceding vowel: árrow, márrow, búrrow, fúrrow, Térry, Dérry, cúrry, sórry, mérry, márry, hárry, húrry. And also in bárrack, bárrier, cárrot, érror, térror, jàrring, bàrring, hárrier, férret. Sometimes it doubles after other sounds: für + -y = fürry, and wòrry (AmE wörry, effect of w on o). And of course before -ed and -ing added to words ending in r: stàrring, bàrred (cf. bŏred, from bŏre, which ends in e). But not always: véry, árid, and never after the sound ã: fãiry, vãry.
rh from initial Greek r, occurs at the beginning of some words; the h is redundant: Rhôdes, rhodedéndron, rhôdium, rhêsus, rhétoric, rhetórical, rhýthm, rhŷme, rhûbarb, rhápsody, rhêa (a as schwa: *rìə) rheûmatism, rheumátic, and beware of diarrhoêa.
wr, too, is, pronounced r; it too tends to appear at the beginning of words, some very common: wrîte read (= rîght correct, side) wróng, wrétch poor (= rétch vomit) wrítten, wréck, wrŷ, awrŷ. Rêad and wrîte; rîght and wróng: both r- followed by wr-.