Díky spolupráci jsme sklidili úrodu.

Here díky means thanks to.

So Díky spolupráci... means Thanks to cooperation...

A useful distinction:

• Díky! by itself = Thanks!
• díky + dative noun = thanks to / due to

In this sentence, it introduces the reason something was successful.

Because díky is followed by the dative case.

The base form is:

• spolupráce = cooperation, collaboration

After díky, it changes to the dative singular:

• díky spolupráci = thanks to cooperation

So this is a case ending issue, not a different word.

It is dative singular.

Breakdown:

• spolupráce = nominative singular
• spolupráci = dative singular

This is worth memorizing because díky commonly takes the dative:

• díky tobě = thanks to you
• díky učiteli = thanks to the teacher
• díky spolupráci = thanks to cooperation

It is the past tense.

Czech past tense is usually made with:

• a present-tense form of být = to be
• plus the past participle of the main verb

Here:

• jsme = we are / auxiliary for we in the past tense
• sklidili = past participle of sklidit

So:

• jsme sklidili = we harvested

Because Czech past participles in the plural agree with the gender of the subject.

For we:

• sklidili is used if the group is masculine animate or mixed
• sklidily is used if the group is all feminine or non-masculine

So this sentence suggests that the speakers are:

• a mixed group, or
• a group including at least one male, or
• just using the default textbook-style masculine animate plural

If the speakers were all women, you would expect:

• Díky spolupráci jsme sklidily úrodu.

sklidili is the perfective past form of sklidit, meaning the action was completed.

So it means something like:

• we harvested
• we managed to harvest
• we finished harvesting

By contrast, sklízeli comes from the imperfective verb sklízet, which focuses more on the process or repeated action:

• sklízeli jsme úrodu = we were harvesting the crop / we used to harvest the crop

So in your sentence, sklidili is used because the harvest is presented as a completed result.

úrodu is accusative singular because it is the direct object of the verb sklidit.

Base form:

• úroda = harvest, crop, yield

Object form here:

• úrodu

So:

• sklidit úrodu = to harvest the crop / to bring in the harvest

This is a very common pattern: the thing directly affected by the verb goes into the accusative.

Because jsme is a clitic, and Czech clitics usually go in the second position in the sentence.

In this sentence, the first unit is:

• Díky spolupráci

Then the clitic comes:

• jsme

So the sentence structure is very natural Czech:

• Díky spolupráci jsme sklidili úrodu.

This may feel unusual to English speakers, but it is a normal Czech word-order rule.

Yes. Czech word order is flexible, but different orders can sound more natural in different contexts or put emphasis in different places.

For example:

• Díky spolupráci jsme sklidili úrodu.
  Neutral, natural: the reason comes first.

• Úrodu jsme sklidili díky spolupráci.
  Puts more focus on the harvest.

• Sklidili jsme úrodu díky spolupráci.
  Also possible, especially in speech, but less neutral than the original.

Even when the order changes, the basic meaning stays the same.

Usually, yes.

díky often suggests that the cause is helpful or beneficial:

• Díky tvé pomoci jsme uspěli. = Thanks to your help, we succeeded.

That is why it fits well with spolupráci, which is something positive.

For negative causes, Czech often uses other expressions, such as:

• kvůli = because of, due to

So:

• Díky spolupráci... sounds natural because cooperation is presented as a good thing that led to success.

A rough pronunciation guide:

• Díky ≈ DEE-kee
• spolupráci ≈ spo-loo-PRAA-tsee
• jsme ≈ roughly yz-me or sme in fast speech
• sklidili ≈ SKLI-di-li
• úrodu ≈ OO-ro-doo

A few important pronunciation points:

• í, á, ú are long vowels
• c in Czech is pronounced like ts
• stress is usually on the first syllable of each word

So the sentence has roughly this rhythm:

• DÍ-ky spo-lu-PRÁ-ci jsme SKLI-di-li Ú-ro-du