Learn Hardcore Czech: Moje maminka se bojí létat letadlem, ale vlaků se nebojí. - My mom is afraid of flying by plane, but she is not afraid of trains.

bát se literally means something like “to fear oneself of something”, but in modern Czech you just learn it as one unit: bát se + Genitive = “to be afraid of”.
You cannot say ✗ maminka bojí on its own; it must be maminka se bojí.
Likewise in the negative: maminka se nebojí (“is not afraid”).

So se doesn’t translate directly into English here; it’s just part of the verb’s fixed form.

Can se move? Why do we have Moje maminka se bojí but vlaků se nebojí, and not ale se vlaků nebojí?

Czech has “clitics” (short unstressed words) like se, si, jsem, mi, etc. They usually stand in the second position in the clause.

In Moje maminka se bojí, the first phrase is Moje maminka, so the clitic se comes right after it.
In vlaků se nebojí, the first word (and the emphasized contrast) is vlaků, so se again goes to the second position: after vlaků.

Forms like ✗ ale se vlaků nebojí sound unnatural because se is trying to be in second position after ale, but we normally treat ale as a kind of “zero‑position” conjunction; clitics prefer to follow the first real sentence element (vlaků).

You can say:

Moje maminka se bojí vlaků.
Moje maminka se vlaků nebojí.

Here Moje maminka is the first phrase, so se still comes second. Both word orders are grammatically correct; the chosen order (vlaků se nebojí) puts more contrastive emphasis on vlaků (“but trains, she isn’t afraid of”).

Why is it vlaků and not vlaky or vlak?

Because bát se takes the genitive case, not the accusative or nominative.

vlak = nominative singular (“a train”)
vlaky = nominative plural (“trains”)
vlaku / vlaků = genitive singular / genitive plural

The pattern is: bát se + Genitive

bojím se psa – I’m afraid of a dog
bojím se psů – I’m afraid of dogs
bojím se vlaku – I’m afraid of (a/the) train
bojím se vlaků – I’m afraid of trains

In your sentence it’s about trains in general, so vlaků (genitive plural) is used. ✗ nebojí se vlaky is incorrect with bát se in standard Czech.

Why is the plural vlaků used here? Could it be singular vlaku instead?

Both are possible, but there’s a nuance:

nebojí se vlaku – not afraid of a/the train (often feels more like one train, or the idea of “the train” as a single thing)
nebojí se vlaků – not afraid of trains in general, the whole category

In your sentence, we’re contrasting flying by plane (as a way of travel) with trains as a general mode of transport, so vlaků (general category) is natural.

Why is it létat and not letět? Aren’t both “to fly”?

Czech distinguishes between one specific movement and repeated / habitual movement:

letět – to fly once, a single trip or single direction
létat – to fly repeatedly, habitually, generally

Here we’re talking about a general fear of flying as a way of travel, not about one particular flight, so létat fits:

Moje maminka se bojí létat letadlem. – She is (in general) afraid of flying by plane.
Moje maminka se bojí letět letadlem. – She is afraid to (go on) this flight by plane (a more concrete occasion).

Both are grammatically correct, but they don’t mean exactly the same.

Why is letadlem in that form? Why not létat letadlo or létat v letadle?

Letadlem is the instrumental case of letadlo and it’s used to express the means of transport:

jet autem – go by car
jet vlakem – go by train
letět letadlem – fly by plane
jezdit autobusem – go by bus

So létat letadlem literally means “to fly by means of a plane”.

You can say létat v letadle, but that focuses on the location (“inside a plane”) rather than the standard expression for travelling by plane. In everyday speech, for mode of transport, the instrumental (letadlem, vlakem, autobusem) is the default.

How does bát se work with infinitives? Why is there no word like “to” before létat?

In Czech, you don’t need a separate word like English to; the infinitive form alone plays that role.

bát se + infinitive = “to be afraid to / of doing something”

Examples:

Bojím se létat. – I’m afraid to fly / of flying.
Bojí se mluvit před lidmi. – She is afraid to speak in front of people.

So in your sentence se bojí létat letadlem = “is afraid to fly by plane”. No extra particle like English to is used.

Why is bojí in the simple present, not something like “is being afraid”?

Czech doesn’t have a separate present continuous tense like English “is doing”. The simple present covers both:

bojí se can mean “is afraid” (current state) or “is (generally) afraid” (habitual).

Context tells you whether it’s a one‑time situation or a stable habit. Here it’s clearly a stable characteristic: she doesn’t like flying by plane in general.

What’s the difference between maminka and matka?

Both mean “mother”, but they differ in style and emotional tone:

maminka – diminutive / affectionate form, very common in everyday speech; sounds warm, family-like.
máma – also very common, neutral‑colloquial (“mum”).
matka – more formal, neutral or even a bit cold; used in official documents, biology, or when deliberately distancing yourself emotionally.

So Moje maminka = “my mum/my mom” with a warm tone. Moje matka would sound more formal or emotionally distant.

Why is it Moje maminka? Could I just say Maminka se bojí létat letadlem?

Yes, you can often omit the possessive pronoun in Czech when it’s obvious that you’re talking about your mother:

Maminka se bojí létat letadlem. – perfectly natural
Moje maminka se bojí létat letadlem. – also correct, puts a bit more emphasis on “my mother” (e.g., in contrast to someone else’s mother).

So moje isn’t grammatically required here; it just adds explicit possession or emphasis.

What’s the difference between moje maminka and má maminka?

Moje and má are two forms of the same possessive pronoun “my” for feminine singular nouns:

moje maminka – the fully regular form
má maminka – a shorter, somewhat more stylistic/literary form

They mean the same thing. In modern spoken Czech, moje maminka is more common and neutral. Má maminka may sound a bit more formal, poetic, or old‑fashioned, depending on context. Both are correct.

How does negation work in se nebojí? Why is the ne‑ stuck to bojí and not to se?

The negative prefix ne‑ attaches directly to the main verb, not to the reflexive pronoun:

bojí se – (she) is afraid
nebojí se – (she) is not afraid

You cannot say ✗ se nebojí as two separate words; it’s always one verb nebojí plus se:

Maminka se nebojí vlaků.
Vlaků se nebojí.

The position of se follows the clitic rule (second position); the ne‑ prefix stays glued to bojí.