Čím dřív zapnu počítač, tím dřív ti pošlu e-mail.

It is the standard Czech pattern for English the ..., the .... The first clause sets the condition or degree, and the second clause gives the matching result: Čím dřív ..., tím dřív ... = The sooner ..., the sooner ....

A more literal way to think about it is by how much ..., by that much ..., but for learning purposes it is best to memorize čím ..., tím ... as one fixed construction.

Yes. Čím is historically the instrumental form of co, and tím is the instrumental form of to.

In this sentence, though, they are not being used as ordinary standalone case forms. Together they make a set expression: čím ..., tím .... So it is better to learn the whole pattern than to analyze each word too literally every time.

Dřív means earlier or sooner. Here it is the comparative adverb, so it fits the English idea the sooner.

It belongs with brzy/brzo meaning soon, but the comparative uses a different stem: dřív or dříve. That is normal in Czech, just as English has irregular comparisons like good → better.

Because both halves of the sentence contain the idea the sooner.

• Čím dřív zapnu počítač... = the sooner I turn on the computer...
• ...tím dřív ti pošlu e-mail. = ...the sooner I will send you an email.

That repetition is exactly how the Czech pattern works.

Because the sentence talks about single completed future actions: first turning the computer on, then sending the email.

Czech normally uses perfective verbs for that:

• zapnout → zapnu
• poslat → pošlu

These forms look like present tense forms, but with perfective verbs they usually have future meaning. By contrast, zapínám and posílám are imperfective and mean something like I am turning on / I turn on and I am sending / I send.

You usually learn this as part of each verb’s pattern. Czech verb forms do not always look very similar to the infinitive.

Here:

• zapnout becomes zapnu
• poslat becomes pošlu

So there is some stem change, especially in pošlu, which is not fully predictable from English-speaking intuition. This is very normal in Czech, and dictionaries will list these forms.

Ti means to you. It is the short, unstressed dative form of ty.

With poslat, Czech usually works like this:

• the person receiving something is in the dative
• the thing being sent is in the accusative

So pošlu ti e-mail means I will send you an email.

The longer form tobě is also possible, but it is used when you want extra stress, contrast, or emphasis.

Both are in the accusative singular because they are direct objects.

• zapnu počítač = I will turn on the computer
• pošlu e-mail = I will send an email

They happen to look the same as the nominative because both are masculine inanimate nouns, but grammatically they are still accusative here.

Because ti is a clitic, and Czech clitics usually go in the second position of their clause.

In tím dřív ti pošlu e-mail, the opening unit is tím dřív, so ti comes right after that unit. This is normal Czech word order.

A version like tím dřív pošlu ti e-mail is much less natural because it breaks the usual clitic placement rule.

Yes.

• dříve is a bit more formal or written in tone
• dřív is very common in everyday Czech

For the noun, both e-mail and email are widely used. The choice often depends on style guide, publication, or personal preference. The grammar of the sentence does not change.

Yes. The comma is standard and should be there:

Čím dřív zapnu počítač, tím dřív ti pošlu e-mail.

Czech normally separates these two clauses with a comma in the čím ..., tím ... construction.