NE

It’s a negative word for imperative mood. Equivalent: DON’T

Ne mondj ilyet! – Don’t say such things!

Ne hagyják a tárcájukat a kocsiban, uraim!
Don’t leave your wallets in your cars, gentlemen!

Ne velem üvölts, üvölts az anyáddal!
Don’t roar at me. Roar at your mother!

Double negation again:

Ne csinálj semmit! / Semmit ne csinálj!
Don’t do anything!

SE, SEM

Equivalent: NOR, NEITHER, EITHER

Én sem tudom. – I don’t know, either.
Még ők se értik! – Even they don’t get it!

Semmit sem láttunk a tömegtől.
We didn’t see anything because of the crowd.

Egy percig sem habozik. – She doesn’t hesitate for a moment.

If you want to say ’neither, either’, then ’sem, se’ stays a single negation. Another example:

A fene se tudja! – The hell knows! (literally: Not even the hell knows!)

NEHOGY, HOGY…NE

Equivalent: lest, so that…don’t. You see you have two possibilities in Hungarian. These words are used in sentences expressing a purpose!

Vigyél kabátot, nehogy megfázz!
Take your jacket lest you catch a cold.

Vigyél kabátot, hogy meg ne fázz!
Take your jacket so that you don’t catch a cold.

Watch how they’re used. ’Nehogy’ is followed by full phrasal verbs, the verbal prefix stays with its verb! However, ’hogy…ne’ makes phrasal verbs split apart and verbal prefixes to precede ’ne’!

Use whichever you want to. One is heard as often as the other.

SOHA

Equivalent: NEVER. Used with double negation only unless it forms its own sentence!

Soha nem bántottalak. – I’ve never hurt you.

Soha semmit nem mondasz nekem.
You never tell me anything.

-Hallottál valaha ilyenről? –Soha. >Soha is the sentence itself.
-Have you ever heard about such a thing? –Never.

Another possibility: soha nem = sohasem

Sohasem bántottalak. – I’ve never hurt you.