Pronunciation exercises: /ɒ/ vs /ɔː/

/ɒ/ and /ɔː/ can be easily confused. Moreover there are many native speakers who don't make a difference. See Cot-caught merger. However, to have a good accent in Received Pronunciation it is best to be able to make the difference.

/ɔː/
Some common words containing /ɔː/ include the following:
 * with "oa": abroad - broad
 * with "ough": bought - brought - fought - ought - thought;
 * with "a": water;
 * with "al": almost - already - alter - always - chalk - false - salt - talk - walk;
 * with "all": ball - call - fall - hall - mall - small - talk - walk - wall;
 * with "aw": dawn - hawk - lawn - shawl - yawn;
 * with "au": auction - August - author - autumn - caught - cause - clause - daughter - fault - launch - taught;
 * with "or": afford - born - cork - fork - horse - lord - pork - short - storm - sword;
 * with "oar": board
 * with "our": court
 * with "ar": quarter - warm - warn;


 * homophones: bored/board - court/caught - stork/stalk.

V is any vowel.
 * /ɔːrV/
 * boring - choral - glory - Laura - storage - story

/ɒ/

 * with "o": doll - golf - hot - lot - off - on - stop - top;
 * with "ong": long - song - strong - wrong;

V is any vowel.
 * others: gone - knowledge - want - what.
 * /ɒrV/
 * with "o": borrow - foreign - horror - orange - sorrow - sorry - tomorrow
 * with "a": warrant - warranty

/ɒ/ vs /ɔː/
There are very few minimal pairs. The most famous of them is cot-caught. Many Americans pronounce identically these two phonemes, and comprehension is not affected. See Cot-caught merger.
 * cot - caught; Don - Dawn
 * coral - choral


 * often - orphan: /ɒ/ vs /ɔː/ in Received Pronunciation. /ɔː/ vs /ɔːr/ in General American. And at both sides of the Atlantic the "t" of "often" may be pronounced.