Jedna židle stačí.

Because židle is a feminine noun.

In Czech, the word for one changes to match the noun’s gender, number, and case:

• jeden = masculine
• jedna = feminine
• jedno = neuter

Since židle is feminine, you say jedna židle.

Yes, here it is singular.

A tricky point: židle can look the same in the nominative singular and the nominative plural. So by itself, židle could mean chair or chairs, depending on context.

In this sentence, jedna makes it clearly singular:

• jedna židle = one chair

If it were plural, you would not use jedna.

Stačí is the 3rd person singular present tense form of the verb stačit.

So:

• stačit = to be enough / to suffice
• stačí = is enough / suffices

It is singular because the subject, jedna židle, is singular.

For comparison:

• Jedna židle stačí. = singular subject
• Dvě židle stačí. = plural subject, but the verb form is still stačí in the present tense because Czech 3rd person singular and plural can look the same with this verb

Because stačí already means is enough or suffices.

English uses to be + enough:

• One chair is enough

Czech often uses a single verb:

• Jedna židle stačí

So you do not add je here.

They are in the nominative singular.

That is because jedna židle is the subject of the sentence.

Also, jedna agrees with židle:

• feminine
• singular
• nominative

So the phrase works as one unit: jedna židle.

Yes. That is completely natural Czech.

Czech word order is more flexible than English, so both are possible:

• Jedna židle stačí.
• Stačí jedna židle.

The basic meaning stays the same, but the emphasis shifts slightly.

A rough way to think about it:

• Jedna židle stačí. = neutral statement about one chair
• Stačí jedna židle. = slightly more emphasis on being enough

You can say Židle stačí, but it is less explicit.

Without jedna, the sentence depends more on context. It could mean something like:

• A chair is enough
• The chair is enough
• A chair will do

Using jedna clearly emphasizes the number one:

• One chair is enough

So jedna is especially useful if you are contrasting it with two or more.

A simple English-friendly guide is:

YED-na ZHID-leh sta-CHEE

A few sounds to notice:

• j = like y in yes
• ž = like the s in vision
• č = like ch in church
• í = a long ee sound

Czech stress usually falls on the first syllable of each word:

• JED-na
• ŽI-dle
• STA-čí

You simply negate the verb:

Jedna židle nestačí.

The prefix ne- makes stačí negative:

• stačí = is enough
• nestačí = is not enough

This is a very common pattern in Czech.

Yes. Very often stačit is used with the dative to show for whom something is enough.

Examples:

• Jedna židle mi stačí. = One chair is enough for me.
• Jedna židle nám stačí. = One chair is enough for us.

Here:

• mi = to/for me
• nám = to/for us

So the thing that is enough is in the nominative, and the person affected is often in the dative.