I also had a lot of trouble with spelling this at first. I've found that it's easier once you know the phonics. Dziewczynka For example, "cz" makes the English /ch/ sound, and "y" makes the /ih/ sound. I'm still not sure about the rules for "z", but it often makes the /zh/ sound, which is kind of like a 'soft' "j" sound, like in "pleasure". Then d+zh 'hardens' it into a j sound.
Oh my, my! All our family arranged a few days in Krakow as a surprise for my husband's birthday. It's only a few weeks away, so I thought that it might be useful to learn a few helpful phrases. Needless to say, I didn't reckon with this! I have learnt several languages in the past, some that were considered difficult, but this one takes the biscuit! It sounds beautiful though. :-)
Polish nouns inflect for 7 cases. Dziewczynka is nominative (base form) and dziewczynką is instrumental:
Ą is a letter that represents a nasal o-sound: https://en.wiktionary.org/wiki/%C4%85#Pronunciation