The /3/ vowel is spelled with <er>, <ir>, <ear>, <ur>, and <or> in word. The /ɪə/ diphthong is spelled <ere>, <eer>, <ear>, <eir> in weird and <ie> in lien. Notice the homograph Wear, here the name of a river.
This is a contrast between a long vowel and a diphthong. The starting positions are well separated in the mouth, but there is a potential problem for learners who try to articulate the post-vocalic -r.
Interesting pairs include:
erring earring
The density figure is 1.46%. The set makes 24 semantic contrasts giving a loading of 53.3%.
bird beard birds beards burr beer burrs beers err ear errs ears erring earring fir fear firs fears fur fear furs fears furze fears gird geared her hear hers hears learn lien learns liens myrrh mere per peer per pier purr peer purred peered purring peering purrs peers purr pier purrs piers purse pierce pursed pierced purses pierces pursing piercing spur spear spurred speared spurring spearing spurs spears stir steer stirred steered stirring steering stirs steers were Wear were weir whirr Wear whirr weir whirrs weirs whirred weird word weird wordy weirdie
Credit: John Higgins