Final answer:
The vowel sound "or" in "supporter" is spelled with the letters 'o' and 'r'.
Step-by-step explanation:
The vowel sound "or" in the word "supporter" is spelled with the letters 'o' and 'r'.
When analyzing the phonetic components of English words, it's important to identify the letters or combinations of letters that represent specific sounds.
The 'or' sound can often be found spelled as these two characters consecutively, as they are in this instance within the word "supporter."
Hence, The vowel sound "or" in "supporter" is spelled with the letters 'o' and 'r'.