The spelling of /t/ is usually <t>, <te> or <tt>, but we also often see <ght> in sight. The /ð/ sound is <th> or <the>. I have included plural pairs sich as baits/bathes, even though they are not strictly minimal, on the grounds discussed under "Problems" in the main article.
The contrast is between a voiceless plosive and a voiced fricative, close together in the mouth. The fact that /ð/ does not occur in many languages makes it a problem for some learners.
This contrast is memorably exploited by Lewis Carroll in Alice in Wonderland when the Mock Turtle describes his school subjects as "Reeling and Writhing, ... Ambition, Distraction, Uglification, and Derision" (reading and writing, addition, subtraction multiplication and division).
One taboo word pair is farting/farthing.
Interesting pairs include:
nitre neither
pretty prithee
skating scathing
The mean density value is 0.5%. The list makes 48 semantic distinctions, a loading of 62%.
bait bathe baiting bathing baits bathes blight blithe boot booth boots booths cite scythe citing scything cites scythes farting farthing fetter feather fettered feathered fettering feathering fetters faethers height Hythe late lathe letter leather letters leathers lettering leathering lettered leathered letterhead Leatherhead light lithe lout Louth mutter mother muttered mothered muttering mothering mutters mothers nitre neither potter pother potters pothers pretty prithee right writhe righting writhing rights writhes rite writhe rites writhes seat seethe seating seething seats seethes sheet sheathe sheeting sheathing sheets sheathes sight scythe sights scythes sighting scything site scythe sites scythes skating scathing suit soothe suits soothes T thee tail they'll tare their tares theirs tat that tats that's tattered that'd tattle that'll teat teethe teats teethes ten then tense thence tie thy tight tithe tights tithes tine thine to the toe though toes those tow though tows those T's these Tyne thine utter other utters others wetter weather whit with witty withy
John Higgins, Shaftesbury, February 2010.