The /ɑ/ vowel is usually spelled <ar> but we also find <a> in ta and <aa> in baa. Notice how the homograph baas enters into two different pairs. The /ʊə/ diphthong is spelled <oor>, <our>, <ure>, or <ue> in cruel.
This contrast is between a long vowel and a diphthong. The starting tongue positions are fairly well separated and confusions are unlikely.
Interesting pairs include:
kraal cruel
parley poorly
The density value is 2.94%. The pairs make 17 semantic contrasts, giving a loading of 54.8%.
ajar adjure baa Boer baas Boers baa boor baas boors baas bourse bar Boer bars Boers bar boor bars boors barn bourne barns bournes guard gourd guards gourds kraal cruel lard lured mar moor marred moored marring mooring mars moors pa poor par poor parr poor parley poorly spar spoor spars spoors ta tour tar tour tarred toured tarring touring tars tours
John Higgins, Shaftesbury, November 2009