Phonological rules for phoneme [ r ]

(a) a rather different [ r ] sound is found at the beginning of a syllable if it is preceded by [ p t k ] it is then voiceless and slightly fricative.

Examples:
– press / prɛs /
– pray/ preɪ /
– approve / əpruːv /
– cream / kriːm /
– increase / ɪŋkriːs /
– crack / kræk /
– tree / triː /
– try / traɪ /
– attract / ətræk/

(b) this phoneme only occurs before vowel:
– red /rɛd/
– arrive /əˈraɪv/
– hearing /ˈhɪərɪŋ/

(c) [ r ] is not pronounced when
– [ r ] is at the end of a vowel : car , ever
– [ re ] is at the end of a word : here / hɪə/, cares / kɛəz /
– [ r ] is immediately followed by a consonant ; hard /hɑːd/ , verse/ vɜːs /, transport / trænspɔːt/

(d) At the end of words, rapid pronunciation has [ r ] only if the immediately following word begins with a vowel, so the word / never /, if it occurs before a pause or before a word beginning with a consonant as in ( never better: / nɛvə bɛtə /) is pronounced: / nɛvə / with no [ r ] in rapid speech. But in (never again / nɛvə (r) əgeɪn ) where it is immediately followed by a vowel, so that [ r ] is pronounced. This is called the liking [ r ].

For examples:
– better off / bɛtə(r)ɔf/
– here it is /hɪə (r) ɪt ɪz/
– poor old town / pʊə(r ) əʊld taʊn/