Mam czternaście dni.

Mam is the 1st person singular present form of the verb mieć, which means to have.

So:

• mieć = to have
• mam = I have

That is why Mam czternaście dni means I have fourteen days.

In Polish, the subject pronoun is often omitted when it is clear from the verb ending.

• mam already means I have
• so ja mam is possible, but ja is usually unnecessary

You would add ja only for emphasis or contrast, for example:

• Ja mam czternaście dni, a on ma tylko trzy. = I have fourteen days, and he has only three.

Because after 14, Polish uses the genitive plural form of the noun.

The basic singular form is:

• dzień = day

But after numbers like 5, 6, 7 ... 14 ... 20 ..., the noun usually appears in the genitive plural:

• pięć dni = five days
• czternaście dni = fourteen days

So:

• dzień = singular dictionary form
• dni = plural form used here after the numeral

Dni is in the genitive plural.

This happens because many Polish numerals, especially 5 and above, require the noun to take the genitive plural.

So grammatically:

• czternaście governs
• dni = genitive plural of dzień

This is a very common pattern in Polish number phrases.

That is a very good question. In Polish, numbers ending in 2, 3, 4 often take the nominative plural form of the noun:

• dwa dni
• trzy dni
• cztery dni

But the teen numbers are an exception:

• dwanaście dni
• trzynaście dni
• czternaście dni

Even though 14 ends in 4, it behaves like the higher-number pattern, not like plain 4.

A useful shortcut:

• 2, 3, 4 → usually special plural pattern
• 12, 13, 14 → do not behave like 2, 3, 4
• 5 and up → usually genitive plural

Here are some useful comparisons with day:

• jeden dzień = one day
• dwa dni = two days
• trzy dni = three days
• cztery dni = four days
• pięć dni = five days
• czternaście dni = fourteen days
• dwadzieścia jeden dni = twenty-one days
• dwadzieścia dwa dni = twenty-two days

Notice that dzień changes depending on the number.

In this sentence, czternaście is in its basic form.

For a beginner, the important thing is that czternaście means fourteen and combines with dni in the normal way:

• czternaście dni = fourteen days

Later on, you may learn that numerals can change form in some grammatical contexts, but here you can treat czternaście as the standard form used in a simple statement.

The neutral, standard order is:

• Mam czternaście dni.

Polish word order is more flexible than English, so other orders are possible, but they usually sound marked or emphasize something:

• Czternaście dni mam. = more emphatic or contrastive
• Dni mam czternaście. = also marked, less neutral

For normal everyday use, Mam czternaście dni is the safest choice.

No. Mam czternaście dni specifically means I have fourteen days.

To say I am fourteen years old, Polish uses the verb to have, but you must say years:

• Mam czternaście lat.

So:

• Mam czternaście dni. = I have fourteen days
• Mam czternaście lat. = I am fourteen years old

This is an important difference for English speakers, because Polish uses have for age.

A rough English-friendly guide is:

• mam ≈ mahm
• czternaście ≈ chter-NAHSH-cheh
• dni ≈ dnee

A few helpful sound notes:

• cz sounds roughly like ch in chop
• ś/si-type sounds are softer than plain English sh
• dni is pronounced as one syllable-like cluster with a clear dn start

A rough full pronunciation guide:

• Mam czternaście dni ≈ mahm chter-NAHSH-cheh dnee

Yes, but dzień is a slightly irregular noun, so its forms are worth memorizing.

The most useful forms are:

• dzień = day
• dni = days

So even though the singular and plural look quite different, dni is the normal plural form you need.

For learners, it is best to remember the pair:

• dzień → dni

Because Polish does not have articles like English a/an and the.

So Polish simply says:

• Mam czternaście dni

English needs something like:

• I have fourteen days

But Polish does not add separate words for articles. The meaning comes from context instead.