How to pronounce 不定 in Cantonese (5 out of 6):

有時候也可以很快消失 所以不定
Sometimes it's just so fast, it's uncertain.

Cantonese Sentence Breakdown

有時候 jau5 si4 hau6
sometimes
jaa5
also
too
(in Classical Chinese) final particle implying affirmation
neither
either
even
as well
still
likewise
可以 ho2 ji5
(adjective) so so
han2
very
faai3
fast
消失 siu1 sat1
disappearance
所以 so2 ji5
hence
不定 bat1 ding6
indefinite
dik1
of
~'s (possessive particle)
(used after an attribute)
(used to form a nominal expression)
(used at the end of a declarative sentence for emphasis)
truly
really
indeed
target
to lift up
few
small
to fetch
to move
to get
to pick up
to force