Okay first the disclaimer: this website is inhabited predominantly by people who independently study Latin and Greek. Non of us (as far as I know) are professionals or experts (well.. some i would regard as experts). I consider myself no more than an intermediate learner of Latin, and accordingly if you take up my suggestions you do so at your own risk – for a tattoo you may wish to contact professionals.
The biggest problem is the word ‘Ducky’, because latin words don’t end with ‘y’. I suppose the third declension would simply apply…
Alternatively you could translate the word ‘duck’, which would be ‘anas’, but if you want to use it as a proper name you may prefer to stick with Ducky. Then again, something like ‘Duckynis’ just looks awful, and I really don’t think you should use it.
On the other hand, according to Diogenes, Plautus (and perhaps others) apparently used ‘anaticula’, i.e. little duck, or ‘duckie’, as a term of endearment, and it may therefore be very appropriate to use the latin term in this case.
I have placed the word ‘est’ (meaning ‘is’) in brackets below, because it is not necessary to add it in Latin. Personally I think it looks much nicer without, although it is perhaps grammatically clearer to add it.
So, I belong to ducky could be:
Anaticulae insum. (which I think is quite nice)
Property of ducky could be:
Res Anaticulae / Possessio Anaticulae
My heart belongs to Ducky could be:
Anaticulae [est] Cor Meum / Cor meum Anaticulae [est]
My soul belongs to ducky:
Anima mea Anaticulae [est]
“Cum ego verbo utar,” Humpty Dumpty dixit voce contempta, “indicat illud quod optem – nec plus nec minus.”
“Est tamen rogatio” dixit Alice, “an efficere verba tot res indicare possis.”
“Rogatio est, “Humpty Dumpty responsit, “quae fiat magister – id cunctum est.”