The spelling of /d/ in this list is <d> or <dd>. The /Ɵ/ sound is spelled <th>.
The contrast is between a voiced plosive and a voiceless fricative, close together in the mouth. It is a problem for many learners, especially French, Italian and Chinese. The distinction in voicing may help, but the use of the <th> spelling for both /Ɵ/ and /ð/ is potentially confusing for learners. Particular problems may arise in final clusters where /Ɵ/ is part of an abstract noun or an ordinal number, such as the sets filled/filth, weld/wealth, ten/tend/tenth or thousand/thousandth. Even native speakers may encounter confusions here.
Interesting pairs include:
The mean density value is 1.5%, but there is a very large discrepancy in frequency between the two sounds, with /d/ occurring in over 19,000 words while /Ɵ/ occurs in under 1,600. The list makes 90 semantic distinctions, a loading of 67%.
ardour Arthur baa'd bath bard bath bards baths barred bath bead Beith bird berth birds berths bode both body bothy bread breath breads breaths cad Kath clod cloth clods cloths dacha thatcher dachas thatchers Dane thane Danes thanes dank thank daw thaw daws thaws daw Thor dawn thorn dawns thorns dead death deadly deathly dearest theorist dearie theory dearies theories deft theft deign thane deigns thanes deism theism deist theist deists theists Dereham theorem Di thigh Dick thick dicker thicker die thigh dies thighs din thin dinned thinned dinning thinning dins thins dinner thinner dirty thirty dirties thirties dole thole doles tholes door thaw doors thaws door Thor Doug thug drawl thrall drawls thralls dread thread dreaded threaded dreading threading drew threw drew through drift thrift drill thrill drilled thrilled drilling thrilling drills thrills drive thrive drives thrives driving thriving drove throve drone throne drones thrones drone thrown drum thrum drummed thrummed drumming thrumming drums thrums dud doth dud thud duds thuds dues thews dug thug dugs thugs dumb thumb dumbs thumbs dumbing thumbing dumbed thumbed dump thump dumped thumped dumping thumping dumps thumps durable thurible durables thuribles durst thirst endues enthuse erred earth fade faith filled filth ford forth ford fourth fords fourths furred firth gird girth girds girths gnawed north god Goth gods Goths had hath hard hearth heed heath held health keyed Keith kid kith knead 'neath kneed 'neath lard lath load loath mead Meath mid myth mod moth mowed mouth need 'neath ode oath order author orders authors overdrew overthrew panda panther pandas panthers pander panther panders panthers purred Perth raid wraith raids wraiths road wroth rod wrath rode wroth rood ruth rowed wroth rude ruth rued ruth said saith slewed sleuth slowed sloth strewed strewth sward swath teed teeth tend tenth tends tenths thousand thousandth trued truth warmed warmth weld wealth welled wealth whirred worth word worth wordless worthless you'd youth
John Higgins, Shaftesbury, February 2010.