Learn Hardcore Czech: Dnes jdu pěšky ke škole.

jdu clearly marks 1st person singular (I go / I am going).
Adding já is only needed for:
- emphasis: Já dnes jdu pěšky ke škole. (I am walking today, not someone else.)
- contrast: Já jdu pěšky, on jede autobusem.

So:

Dnes jdu pěšky ke škole. – neutral, natural Czech.
Já dnes jdu pěšky ke škole. – sounds a bit emphasized.

What is the difference between jít and jet? When do I say jdu?

Czech has different verbs for “go” depending on the means of transport:

jít – to go on foot
- jdu – I go / I am going (on foot)
- jdeš, jde, jdeme, jdete, jdou
jet – to go by vehicle (car, bus, train, bike, etc.)
- jedu – I go / I am going (by transport)
- jedeš, jede, jedeme, jedete, jedou

So:

Dnes jdu pěšky ke škole. – I’m walking to (towards) the school.
Dnes jedu autobusem ke škole. – I’m going to (towards) the school by bus.

If you say jdu, it automatically means on foot, even without pěšky (though pěšky makes it explicit).

If jdu already means “I go on foot”, why do we add pěšky? Is it necessary?

pěšky means “on foot”, and it is an adverb.

jdu by itself usually implies walking, yes.
But in real speech, pěšky is very common for clarity or emphasis.

Comparisons:

Dnes jdu ke škole. – Today I’m going to/towards the school.
(Context usually suggests walking, but it is not totally explicit.)
Dnes jdu pěšky ke škole. – Today I’m walking on foot to/towards the school.
(Clearly contrasts with going by bus, car, etc.)

So pěšky is not strictly required grammatically, but it’s natural and helpful in everyday speech.

What exactly is pěšky grammatically, and how is it used?

pěšky is an adverb meaning “on foot”.

It comes from the adjective pěší (pedestrian, on foot), but as pěšky it no longer changes its form; it’s invariable.
You usually use it with motion verbs:
- jít pěšky – to go on foot
- chodit pěšky – to walk (habitually) instead of using transport
- jezdit pěšky – not used; you cannot “ride on foot”

Examples:

Do práce chodím pěšky. – I (usually) go to work on foot.
Dnes nejdu autobusem, jdu pěšky. – Today I’m not going by bus, I’m walking.

Why is it ke škole and not k škole?

The basic preposition is k (to, towards), used with the dative case.
However, Czech often adds -e for easier pronunciation, giving ke.

You use ke mainly:

before words where k + consonant cluster would be hard to pronounce,
typically before words starting with k, g, h, ch, s, z, ř and some consonant clusters.

škole starts with š, so k škole is awkward. Czech therefore prefers:

ke škole – natural, correct
k škole – sounds wrong to native speakers

Other examples:

k domu but ke kostelu
k vodě but ke dveřím

Why is it ke škole and not do školy? Don’t both mean “to school”?

Both talk about direction, but the nuance is different:

k / ke
- dative = towards, up to, near something
  It focuses on approaching a place, being near it.
- jdu ke škole – I’m walking towards the school / to the area of the school. It doesn’t say whether you go inside.
do
- genitive = into, inside
  It emphasizes entering something.
- jdu do školy – I’m going to school (into the building / to attend it).

In practice:

Dnes jdu pěšky do školy. – I’m walking to school (to attend, enter).
Dnes jdu pěšky ke škole. – I’m walking to the school area / up to the school.
(Maybe to meet someone in front of it, not necessarily to go in.)

Both are correct; which one you choose depends on what you want to emphasize.

What case is škole, and how does škola decline?

The noun škola (school) is feminine. In ke škole, it is in the dative singular, because the preposition k / ke always takes dative.

Simplified singular declension of škola:

Nominative (who? what?): škola – the school
Genitive (of?): školy
Dative (to / for whom?): škole
Accusative (whom? what?): školu
Locative (about / in?): škole
Instrumental (with?): školou

So:

ke škole – to/towards the school (dative)
do školy – to/into the school (genitive)
ve škole – in the school (locative)
se školou – with the school (instrumental)

Can I change the word order? For example, is Jdu dnes pěšky ke škole also correct?

Yes. Czech word order is relatively flexible, especially for adverbs like dnes and pěšky. All of these are grammatical:

Dnes jdu pěšky ke škole. – Today I’m walking to/towards the school.
(Neutral, typical order: time – verb – manner – destination.)
Jdu dnes pěšky ke škole. – I’m walking to the school today.
(Slightly different rhythm, still neutral.)
Jdu pěšky dnes ke škole. – Still possible, but sounds less natural; dnes usually comes earlier.

The default, most natural version is very close to what you already have:

Dnes jdu pěšky ke škole.
Or: Dnes jdu ke škole pěšky. (also fine)

In English we say “I’m walking…”. Why is Czech using a simple present jdu, not a special continuous form?

Czech does not have a separate continuous/progressive tense like English “I am walking”.
The present tense covers both:

a current, ongoing action:
- Teď jdu ke škole. – I am going / I’m on my way to the school now.
a near-future, planned action (in some contexts):
- Dnes večer jdu do kina. – I’m going to the cinema this evening.

In your sentence:

Dnes jdu pěšky ke škole.
will usually be understood as a plan for today or something that is happening today, and is translated as:
- Today I’m going (walking) to/towards the school.

What’s the difference between jít (jdu) and chodit (chodím) in similar sentences?

Czech distinguishes:

jít – one specific movement in one direction (single event)
chodit – repeated / habitual movement, or movement in various directions (habit or general ability)

Compare:

Dnes jdu pěšky ke škole.
– Today I’m going (this one time) on foot to/towards the school.
Do školy chodím pěšky.
– I (usually / regularly) walk to school (that’s my habit).

So:

For today’s specific plan: Dnes jdu pěšky ke škole.
For a general routine: Do školy chodím pěšky.

Is there a more explicitly future version, like “Today I will walk to school”?

Yes. To stress the future, you can use the future form of the motion verb:

půjdu – future of jít (I will go, I will walk)

Examples:

Dnes půjdu pěšky ke škole. – Today I will walk to/towards the school.
(Sounds like a decision or plan.)

In many contexts, Dnes jdu pěšky ke škole already implies future (a plan for later today), so Czech often uses just the present. You choose půjdu if you really want to highlight the futurity or the decision.