These are past tense verbs/past participles created from base words that end in a voiceless sound, plus the suffix ‘ed’. When we add ‘ed’ it becomes voiceless to match the base word, so it sounds like ‘t’.

When a base word ends with a ‘short’ vowel then one consonant letter, we double the last consonant before adding suffixes starting with vowels. This maintains the “short” vowel sound: 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).

Base word ends with 2-3 consonant lettersDouble last consonant of CVC base word before adding edDouble last consonant of longer/more complex base word before adding ed
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