What is wrong with Cobalt Zosia, or Polish female names in the fantasy literature

Lately, I saw this:

And of course I laughed very hard. Why I did that? It’s a legal Polish name, right? It certainly sounds Polish?
As in many other European languages, many Polish names have a diminuitive form, or forms. They are used by friends, acquitances and in an informal setting. They are often endearing. Children get only called by the diminuitive forms.

Native English writers LOVE diminuitive forms, because they sound so “Polish” and confuse them with original names all the time. As a general rule, if a name is short, and/or contains soft consonants such as “si”, “ci”, “nia”, you should check if it’s a diminuitive form of an otherwise serious name.

Zosia (read approx. as Z-OOH-SE-AH) is a diminuitive from Zofia. Nobody would call a legendary general Zosia. It would induce feats of laughter, and would be probably an offense with corporal punishment if addressed to her in a battlefield. Unless she’s a leader of a mercenary group, and everybody is befriended with each other enough to drop formalities, they will call her Zofia.

Zosia is a name you would use for your friend, or a little girl, or your subordinate. Not for your higher-up for sure.
Now, it gets more complicated.
Zofia can be also abbreviated to Zośka, Zocha or Zosieńka.

Zośka (read approx. as Z-OOH-SE/SH-K-AH) is a diminuitive used among friends and in very informal settings. It can be also used by general Zofia’s soldiers, but only when she’s not listening, or they are very familiarized with her (as in, blood bond, drinking together, you call it).

Names abbreviated with -śka, -nka, will be used among farm girls and boys of equal age, among adult companions of equal age (even nobility), and also today. Used in a wrong context (for example directly to your boss), it will cause offense.

The same goes for Zocha (read approx. as Z-OOH-hard H- AH) , but this is an augmentative form. It suggest someone with a powerful frame, older, larger, perhaps intimidating. It is also even more colloquial, even a bit degrading and mildly offensive unless used jokingly among friends. You don’t call a general Zocha, definitely not in her presence. Nobles will not use this form between each other. Villagers (as in - Zocha! Cho no tu! (come here)), a gang of thieves, or a band of teenagers will. People would call each other augmentatives as a part of low social strata slang.

On the other hand, Zosieńka is a very endearing form used by a mother to a little child or by a lover in an emotional context. When a literary character uses that form, things are going to get all sobby. It is also rarely used today.

In any case, it should be general Cobalt Zofia. It’s how they will put it in the chronicles. Or, if we want to get it right, Kobaltowa Zofia. (koblatova zofyah).

I’ll get you a few more examples. They aren’t intuitive, for example Justynka would be an equivalent to Zosia, and not to Zośka. So to make things easier, I’ll grade diminuitives and augmentatives. Not every name has all forms.
Grade 1 - Zosia - child/endearing/friend/subordinate
Grade 2- Zośka - colloquial/good friend/sibling/informal
Grade 3 - Zocha - augmentative/strongly informal/mildly pejorative
Grade 4 - Zosieńka - loving/very endearing/old fashioned

Anna: Ania (1), Anka (2), Anusia (4)
Katarzyna: Kasia (1), Kaśka (2), Kacha (3), Kasiuchna, Kasieńka (4)
Justyna: Justynka (1), Justysia (4)
Elżbieta: Ela (1), Elżbietka (1 or 4), Elka (2 or 3) (depending on the tone of voice and context…).
And let’s complicate some more:
Aleksandra: Ola (1), Olka (2/3), Oleńka (4).

Oh, why is it so damn hard? Why can’t I just use a Polish name in a fantasy setting?

Well, it’s easy, really.
Either use ONLY the official forms (Polish readers will be less bothered), or ask your Polish friends/cousins. Remember, the same goes for male names. If you call a general Zenek, or Jędruś, you’re in for a fit of healthy laughter. Also, as a general rule, if you want to use menacing names, choose the ones without soft consonants (there are exceptions, but this rule is easy).

If you by any chance actually know what you’re doing, use diminuitives anyway. Naomi Novik is probably aware that “Kasia” is an appropriate nickname for a young village woman and uses it. Edit: My friend, who as read the English version, says that even Novik failed at this, calling the prince, then king, "Mareczek" - which is a very cordial diminuitive for "Marek". Unless you got drunk with the guy, and it's your close relative, you don't call that an adult royal. Actually even if it IS your close relative, in the royal family this form is reserved for private quarters.

But I want to use the names with all your weird sounds and consonants! They sound exotic, while your regular names are so… alike any other European names!

Of course they are. We we’re from the same Latin/Greek culture after all. Western Catholicism played a great part in the development of Polish culture from approx. 1000 AD, in contrary to Russia, where Eastern Orthodox influences can be seen. Some Slavic traditional names remain, but, at large, you can use names such as:

Agnieszka
Katarzyna
Elżbieta
Małgorzata
Urszula
And yes, Zofia!

Or other Polish versions of European names that you don’t know how to spell.

Or, if you feel courageous, use Slavic names such as:

Nawojka
Bogumiła
Bogna
Dobrawa
Lubomiła
Milena
Mira
Grażyna (it’s not a real traditional name - it was invented by a Polish poet Adam Mickiewicz and stuck as a proper name, also: it is currently used as a derogatory nickname)

Or just look in here! :D (warning: hilarity risk - some of those are really antiquated).