Yes, I’m kidding – R isn’t actually a vowel, it just gets used as a vowel substitute and gives itself a bad name.
Rs at the front ends of words don’t usually create a problem as long as they’re over and done with instantly, and we get on with the real business of singing – pure, clean vowels.
However, Rs at the back end of a syllable can cause no end of trouble, because our minds and our tongues know they’re coming. You can hear tongues tightening more and more throughout the choir, and the sound becomes less and less resonant till mercifully it’s time for the word to be over.
There’s a whole tradition of choral music that has handled the problem by eliminating the Rs altogether, by pretending that the choir members all speak with the English accent that replaces final Rs with a version of ‘ah’. While this is an accepted idiosyncrasy of the men and boys’ choir idiom, it draws attention to itself when adopted by other singing groups. (And anything that draws attention to itself will upstage the song)
The quick fix is to have choir members place the tip of the tongue halfway up the back of the bottom front teeth, and keep it there – relaxed relaxed relaxed – while singing all the R they want.
The other approach will give a more resonant sound, but takes a little longer because the mind needs to be drilled for it to become a habit.
Whatever the target vowel is – whether it’s long, short, formed or unformed, the usual care needs to be taken with matching and relaxation. Then, just as the sustained syllable is about to move to the next word, we sing the resolution sound – er, ert, erm, erd or erld.
Here are some examples:
Are = Ah—————–er (Formed vowel – Ah)
Ever = Ehveu————er (Unformed neutral vowel – relaxed mouth)
Fair = Feh—————-er (Relaxed mouth)
World = Weu————erld (Unformed neutral vowel – relaxed mouth)
Near = Nee—————er (Formed vowel – Ee)
Arm = Ah—————-erm (Formed vowel – Ah)
Heart = Hah————–ert (Formed vowel – Ah)
Storm = Stoh————-erm (As close to formed Italian ‘O’ as possible)
The real work here is to teach the mind to think only about the target vowel as the sustained pitch is being sung – and then, only at the last millisecond to let the mind think of the R.
However, the sound dividends are so huge, that I find that choirs can get quite excited about the work. Ultimately, glorious sound trumps everything.