OR (for) Sound Word List
The /or/ sound is one of a class of four sounds often referred to as the r-controlled vowel sounds. The four sounds are /ar/ (car), /or/ (for), /er/ (her), and /err/ (merry). This class of vowel sounds has few spelling options.
Of the 7,000 words in the database constructed from a popular children’s dictionary, 49 of them are one-syllable words in which the vowel sound is /or/. The only spellings of the /or/ sound in one-syllable words in the database are "or" and "ar". This list is a good reference for locating words where a preceding /w/ sound changes the pronunciation of the "ar" spelling from the /ar/ sound to the /or/ sound in words like war and quartz.
Although the /or/ sound is technically a combination of two sounds, the /oe/ sound in toe and the /r/ sound in run, but it is best to teach it as a single sound. Otherwise, in testing the vowel sounds, a child trying the /o/ sound for the letter "o", as he should, will end up reading words like form as farm and cord as card when he first encounters them.
Note, though, that spellings like "o-e" and "oa" can be taught as /oe/ sounds and the /r/ sound added in words like shore and oar. Children can be taught to blend those spellings without having to introduce multiple spellings of the /or/ sound.