Moja żona ma urodziny dziesiątego lutego.

Because żona is a feminine noun, and Polish possessive adjectives must agree with the noun in gender, number, and case.

In the nominative singular:

• mój = masculine
• moja = feminine
• moje = neuter

So:

• moja żona = correct
• mój żona = incorrect

Here żona is the subject of the sentence, so it stays in the nominative singular form.

The basic dictionary form is żona, and that is exactly the form you use when saying my wife as the subject:

• Moja żona ma urodziny.

If the noun had a different role in the sentence, its form could change. For example:

• Widzę moją żonę = I see my wife

There, żona changes to żonę because it becomes the direct object.

This is just the normal Polish way to express it. Polish uses the verb mieć (to have) in this expression:

• mieć urodziny = to have a birthday

So Polish does not usually say something literally like is birthday in this context. The structure is idiomatic, and learners simply have to remember it as a set expression.

Very similar examples:

• Mam dziś urodziny. = I have my birthday today / It’s my birthday today.
• Kiedy ona ma urodziny? = When is her birthday?

Because urodziny is normally used as a plural-only noun in Polish. Even though in English birthday is singular, Polish usually says urodziny, which is grammatically plural.

So you say:

• mam urodziny
• ona ma urodziny
• moje urodziny

A more literal singular-style expression does exist:

• dzień urodzin = day of birth / birthday

But in everyday Polish, urodziny is the usual word.

That is the standard Polish way to give an exact calendar date.

For dates, Polish normally uses:

• an ordinal number for the day
• the month in the genitive case

So:

• dziesiątego = tenth
• lutego = of February

Together:

• dziesiątego lutego = on the tenth of February

This pattern is very common:

• pierwszego maja = on the first of May
• trzeciego czerwca = on the third of June
• dwudziestego piątego grudnia = on the twenty-fifth of December

Because dziesiątego does not describe żona. It belongs to the date expression, not to the wife.

You can think of it as referring to an implied word such as dzień (day), which is masculine:

• dziesiątego [dnia] lutego

So the form is not chosen because of żona. It is chosen because Polish dates use this fixed genitive pattern.

Usually no. With exact dates, Polish normally uses no preposition:

• Moja żona ma urodziny dziesiątego lutego.
• Mam egzamin piątego marca.

This is different from some other time expressions, where Polish often does use a preposition:

• w lutym = in February
• w poniedziałek = on Monday

But with a full date such as dziesiątego lutego, no w is normally needed.

Because in Polish, the names of months are normally written with a lower-case letter.

So:

• luty
• marzec
• kwiecień

This is different from English, where month names are capitalized. So lutego with a small l is completely correct.

Yes. In writing, 10 lutego is very common.

But when reading it aloud, you would normally say:

• dziesiątego lutego

So the written number and the spoken form follow the same date pattern.

Yes, Polish word order is more flexible than English word order, although some versions sound more neutral than others.

The most neutral version here is:

• Moja żona ma urodziny dziesiątego lutego.

You could also say:

• Dziesiątego lutego moja żona ma urodziny.

This version puts more focus on the date.

Polish often changes word order for emphasis, topic, or style, not because the grammar changes completely.

Then urodziny changes form:

• Moja żona ma urodziny dziesiątego lutego.
• Moja żona nie ma urodzin dziesiątego lutego.

Why? Because with negation, Polish often changes the direct object from the accusative to the genitive. Since urodziny is a plural noun, the genitive plural form is urodzin.

This is a useful pattern to notice:

• ma urodziny
• nie ma urodzin