I collect words that change their pronunciation when you prefix them with the letter s. Most words, like tone say, don’t change; tone and stone both have oh as the vowel sound and rhyme. But some words, like how say, change vowel sounds when you prefix them with an s and no longer rhyme; how (ow) becomes show (oh).
Here’s my collection so far:
aid
allow
ally
ave
ere
even
hall
have
having
hoe
hone
hovel
how
lather
laughter
linger
lither
lough
now
on
pear
teak
word
Some depend on your pronunciation:
cone
ewer
mall
older (the US pronunciation sounds very rude here in the UK)
troll
and some are a bit dubious:
pud
WALK