These are past tense verbs/past participles created from base words that end in a voiceless sound, so when we add “ed” this becomes voiceless to match, so sounds like “t”.
Doubled consonant letters show that the preceding vowel is pronounced as a “short” vowel: a as in capped (not caped), e as in pepped (not peped), i as in pipped (not piped), o as in copped (not coped), u as in supped (not suped).
backed bashed batched bossed botched buffed cashed checked chocked chucked chuffed cocked cuffed cussed dashed decked dished dissed ditched docked doffed dossed ducked etched fetched fished fussed gashed gassed gushed hacked hatched hissed hitched hocked huffed hushed itched jacked kicked kissed lacked lashed licked locked lucked mashed massed matched meshed miffed missed mocked moshed mucked mushed nicked notched packed patched pecked picked pitched pocked puffed racked retched rocked rucked rushed sacked shocked shucked socked sucked sussed tacked thatched ticked tossed tucked wished |
bopped capped chapped chipped chopped copped cupped dipped hipped hopped kipped lapped lipped lopped mapped mopped napped nipped pepped pipped popped rapped ripped sapped shopped sipped sopped supped tapped tipped topped upped yapped yipped zapped zipped |
blipped clapped clipped clopped cropped dripped dropped flapped flipped flopped gripped plopped prepped propped quipped scrapped shipped skipped slapped slipped slopped snapped snipped stepped stopped strapped stripped swapped trapped tripped whipped wrapped |