The great duck debate

Miss V has inherited her big sisters 'duck' complex. Fortunately J and F have grown out of it, but V still insists that ducks don't say 'quack', they say 'duck', and that all birds are ducks. This wouldn't be a big deal, only she also insists that the word is not 'duck', it's ''.
This makes social gatherings and outings much more interesting.
Fish and chips at the beach usually involves Miss V running amongst the seagulls shouting "!!!" We went to Movie World and she saw Daffy Duck... "Wow! Big!"
Possibly the most awkward was a recent visit to the pond, where there are lots of f.cks and LOTS of people. Miss V ran around telling everyone who'd listen how much she likes f.cks and that we have lots of f.cks in the dam at home. Honestly, I'm surprised I wasn't arrested.
So this morning when the topic came up I decided it might be time to have another go at correcting this little quirk...

V: (excitedly) Look mum!!
Me: (patiently) No V, I see a duck
V: (positively ecstatic) Yes!!!!
Me: (semi patiently) Watch my mouth V, 'duck' D.uck. D. D.uck.
V: (patiently) Ffffuck...
Me: (determinedly) Not fffff, D! D, D, D!
V: (amused) D?
Me: (excitedly) Yes! D! Duck. Dddduck.
V: Yeah mum!!

Me: Oh for f.cks sake