Final answer:
A single vowel letter followed by 'r' that stands for a unique vowel sound indicates r-controlled vowels. There are four ways to spell the [r] sound: , , , and . The vowel sound is typically changed by the presence of , as seen in the spelling and pronunciation patterns in English.
Step-by-step explanation:
In English phonetics, a single vowel letter followed by the letter that represents a unique vowel sound is known as r-controlled vowels or 'bossy R'. The pronunciation of a vowel is significantly changed by the presence of a succeeding . The characteristic sounds are observed in words such as 'car' where the sounds different than in 'cat' because of the influence of .
There are four primary ways of spelling the phoneme [r], which are , , , and . The spelling or is common in English, with typically used after a vowel in a free stem when suffixation occurs. The spellings and are much rarer and typically originate from specific linguistic roots (like German or Greek, respectively).
For instance, the in the word 'overripe' is spelled due to simple addition of a suffix. This phenomenon can also be seen in the word 'underrated.' The spelling in words like 'wrapper' and in the word 'rhetoric' represent more unusual cases of spelling [r]. Oftentimes, in VCV (vowel-consonant-vowel) patterns, if the consonant is , the preceding vowel sound changes distinctly, as in 'dare' versus 'date'.