[Grammar] The r-sound in RP and non-rhotic accents of English

[cipali]

HI everyone.

May I ask you what happens with the "r" in the following words (in non-rhotic accents like RP): beware /bɪˈwɛə/, care /kɛə/, dare /dɛə/, there /ðɛə/, share /ʃɛə/, compare /kəmˈpɛə/, careful /ˈkɛəfʊl/, sphere /sfɪə/, figure /ˈfɪɡə/, and so on? In all of these cases the “r” is neither at the end of the word nor before consonant (rules that many BrE teachers teach for silent "r") – still, it is silent. Are there any rules that can be applied in these cases? What about: very, necessary, arbitrary, and so on - here the "r" is pronounced, but, even though in the middle of the word, there's no consonant before it (other rule BrE teachers teach for non-silent "r")? What's the rule here? What about the words: order, separate and the like? In "order", for example, the "r" is before a consonant - still, it is silent. On the other hand, in "separate" the "r" is in middle position, but there's no consonant before it - still, it is pronounced and therefore non-silent. What I am trying to learn is whether (or not) there are 2 separate rules for the “r”: one telling me when the “r” must be pronounced and one telling me when the “r” is silent. Am I missing something here? Thank you!
P.S.: As I have spoken with other BrE experts, I would also like to ask you if the following conclusions are accurate enough and could be considered a rule for the pronunciation of the "r" sound (in British RP and non-rhotic accents of English):
1. "r" is silent in the following words: car, star, sister, mother, word, person, bird (/kɑː/, /stɑː/, /ˈsɪstə/, /ˈmʌðə/, /wɜːd/, /ˈpɜːsn/, /bɜːd/) because it is not followed by a vowel sound.
2. "r" is pronounced in the following words: read, write, red, Rome, grass, green, very, separate (/riːd/, /raɪt/, /rɛd/, /rəʊm/, /grɑːs/, /griːn/, /ˈvɛri/, /'sepərət/) and also in berry, carry, arrange (ˈ/bɛri/, /ˈkæri/, /əˈreɪnʤ/) because it is followed by a vowel sound.
Or, to sum up: /r/ (the phoneme, i.e. the sound as in red) occurs only before a vowel phoneme (in British RP and non-rhotic accents of English). In every other case, it is silent. Is this enough to be considered a rule? Thank you very much!

 

[Skrej]

Well, different variants handle it differently, but essentially if the 'r' follows a vowel but itself isn't followed by another articulated (note the silent 'e' in some of your examples) vowel, then it's either dropped or switched to something like a schwa or a digraph blend with the preceding vowel, depending on variant and accent.

This Wikipedia article has some good information as well.

 

[cipali]

Thank you all!
I know about the "linking r", "intrusive r", "silent vowels", "r-controlled vowels" and the like phenomena.

The "linking r" occurs in: care about (/keər əbaʊt/), near enough (/nɪər ɪˈnʌf/), war and peace (/wɔːr ənd piːs/), where the "r" sound serves to link 2 otherwise consecutive vowel sounds. Of course this happens only when there is NO pause between them in pronunciation. It happens with isolated words too as in: caring, daring, stirring (/ˈkeərɪŋ/, /ˈdeərɪŋ/, /ˈstɜːrɪŋ/), all of which in their base form would have the silent "r" in pronunciation as in: care, dare, stir (/keə/, /deə/, /stɜː/).
P.S.: My second language is American English. We do have some strange phenomena in AmE as well, but this one with the "r sound" in RP was driving me crazy.

 

[GoesStation]

Americans with non-rhotic accents do the same things.