As adjectives the difference between itty and bitty
is that itty is extremely small, as in itty-bitty while bitty is containing bits; fragmented.
As a noun bitty is
.
itty
English
Adjective
(er)
Extremely small, as in itty-bitty.
bitty
English
Adjective
(er)
Containing bits; fragmented
Very small
Noun
(bitties)