/ar/ /or/

So, just to keep you on your toes, here are two more times the letter r changes the sound of the vowel:

/ar/ spelled as ‘ar’

ar can be found anywhere in a word: art, dart, car — at the start, middle or end of a word.

bark is a homonym (homo = same, nym = name): words that are spelled the same and sound the same but have different meanings like bark (dog bark and tree bark).
Other homonyms:

bat (baseball bat, nocturnal animal)

bank (where you keep you money, at the edge of a river)

See below to read about homonyms, homophones and homographs - the trickiest words to spell.

/or/ spelled as ‘or’

or can be found anywhere in a word, and, of course, is a word all by itself:
organ or corn or for ..

bonus notes

Homophones

Prefix homo-  “the same”

Suffix -phone  “sound”

same pronunciation

different meaning

different spelling

flower, flour

to, too, two

there, their, they’re

your, you’re

by, buy, bye

brake, break

Homonyms

Prefix homo-  “the same”

Suffix -nym  “name”

same pronunciation

same spelling

different meanings

bank (for $, river)

bark (tree, dog)

bat (baseball, animal)

lie (lie down to sleep, untruth)

fall (fall down, autumn)

Homographs

Prefix homo-  “the same”

Suffix -graph  “writing”

same spelling

different pronunciation

different meanings

tear (cry, rip paper)

bow (bow after a performance, ribbon in your hair)

minute (time, small)

close (to be near something, to shut)