Lekce začíná dnes.

Lekce is the subject of the sentence: the thing that is starting.

Grammatically, it is:

• a noun
• feminine
• singular
• in the nominative case because it is the subject

So in Lekce začíná dnes, lekce = the lesson.

Začíná is the 3rd person singular present form of začínat.

It is in this form because the subject lekce is:

• singular
• 3rd person (not I or you, but it)

So the pattern is:

• já začínám = I start / am starting
• ty začínáš = you start
• on/ona/ono začíná = he/she/it starts

Since lekce is grammatically like she/it, Czech uses začíná.

This is about aspect, which is very important in Czech.

• začínat = imperfective
• začít = perfective

So:

• Lekce začíná dnes. = The lesson starts today / is starting today.
• Lekce začne dnes. = The lesson will start today.

Both can be possible in real life, but they feel a little different:

• začíná often sounds more like a scheduled or current fact
• začne focuses more on the single completed beginning as a future event

A learner should know that Czech often uses the present tense of an imperfective verb for timetables, schedules, and near-future events.

No. Dnes is an adverb, not a noun, so it does not take case endings here.

It simply means today.

So:

• dnes = today
• it answers when?
• it stays the same in this sentence

Czech has no articles, so there is no direct equivalent of the or a/an in most sentences.

So:

• lekce can mean a lesson or the lesson
• the exact meaning depends on context

In this sentence, the English translation is probably The lesson starts today, but Czech does not need a separate word for the.

Yes. Czech word order is fairly flexible.

The basic sentence is:

• Lekce začíná dnes.

But you could also hear:

• Dnes začíná lekce.
• Lekce dnes začíná.

These all mean roughly the same thing, but the emphasis changes a little:

• Lekce začíná dnes. → neutral
• Dnes začíná lekce. → emphasis on today
• Lekce dnes začíná. → often slightly emphasizes today within the sentence

Because Czech uses case endings and verb forms, word order is often used more for focus and style than for basic grammar.

A simple approximate pronunciation is:

LEK-tseh za-CHEE-naa dnes

A few helpful points:

• lekce sounds roughly like LEK-tseh
• č is like ch in check
• í is a long ee
• á is a long aa
• dnes is pronounced as one syllable by many speakers, roughly like dness

Also, Czech stress is usually on the first syllable of each word:

• LEKce
• ZAčíná
• DNES

The dictionary form is začínat.

In vocabulary lists, Czech verbs are normally given in the infinitive, so you would learn:

• začínat = to start / to begin

Then začíná is one conjugated form of that verb.

Not only. Lekce can mean:

• a school lesson
• a class session
• a unit in a textbook
• sometimes even a lesson in the abstract sense, as in something learned from experience

In this sentence, the most natural meaning is probably a class or lesson session.

Yes, in some contexts that is a reasonable English translation.

Because začíná is a present-tense imperfective form, it can often be translated in English as:

• starts
• is starting
• sometimes even a scheduled future starts today

The best English version depends on context, but the Czech sentence itself is completely natural.

Yes, dnes is the normal everyday word for today.

Some useful related words are:

• zítra = tomorrow
• včera = yesterday
• teď = now
• brzy = soon

So you could compare:

• Lekce začíná dnes. = The lesson starts today.
• Lekce začíná zítra. = The lesson starts tomorrow.
• Lekce začíná teď. = The lesson is starting now.