Bu bir yalan değil; gerçekten otobüs gecikti.

In Turkish, the verb to be is often not stated as a separate word in the present tense.

So:

• Bu bir yalan. = This is a lie.
• Bu bir yalan değil. = This is not a lie.

The negative word değil does the job of is not / are not in this kind of sentence.

This is very common with noun and adjective sentences in Turkish:

• Bu güzel. = This is beautiful.
• Bu güzel değil. = This is not beautiful.

Değil is the standard negator used for nominal sentences—sentences where the predicate is a noun, adjective, or similar word, not a regular action verb.

In this sentence:

• Bu bir yalan değil.
• literally: This a lie not.
• natural English: This is not a lie.

It is written separately because it is its own word.

Compare:

• gelmedi = he/she did not come
  Here the negation is inside the verb.
• yalan değil = is not a lie
  Here the negation is the separate word değil.

Yes, you can say Bu yalan değil too.

The difference is roughly:

• Bu bir yalan değil. = This is not a lie.
• Bu yalan değil. = This isn’t a lie / This is not false.

Using bir makes it feel more like a lie as a countable noun, which matches English very naturally.

Without bir, the sentence can sound a little more general or categorical, but both are correct.

Gerçekten means really, truly, or genuinely.

Placing it near the beginning gives it emphasis:

• Gerçekten otobüs gecikti. = The bus really was delayed.

Turkish word order is flexible, so you may also hear:

• Otobüs gerçekten gecikti.

Both are correct, but the emphasis shifts slightly:

• Gerçekten otobüs gecikti puts focus on the fact that it was really true.
• Otobüs gerçekten gecikti puts the bus first and sounds a bit more neutral.

Gecikti comes from gecikmek, which means to be late, to be delayed, or to arrive late depending on context.

So otobüs gecikti can be understood as:

• The bus was late
• The bus got delayed
• The bus was delayed

In everyday English, any of these may fit depending on the situation. Turkish often leaves that distinction to context.

Gecikti = gecik- + -ti

• gecik- = verb stem, be late / be delayed
• -ti = past tense suffix

So it means was late / got delayed.

Why -ti and not -di? Because Turkish past tense changes according to sound patterns:

• after certain voiceless consonants, -di becomes -ti

Since the stem ends in k, you get:

• gecik + di → gecikti

This is completely normal Turkish sound harmony/assimilation.

In Turkish, the subject of a sentence is often just the plain noun, with no special ending.

So:

• otobüs = the bus
• Otobüs gecikti. = The bus was delayed.

Turkish does not have articles like the and a/an in the same way English does, so otobüs can mean the bus here because the context makes it definite.

It is written as one sentence with two clauses, joined by a semicolon:

• Bu bir yalan değil;
• gerçekten otobüs gecikti.

The semicolon shows a close connection between the two ideas:

• This is not a lie; the bus really was delayed.

You could also write it as two separate sentences:

• Bu bir yalan değil. Gerçekten otobüs gecikti.

That would also be correct.

Sometimes yes, depending on context, but its core meaning is more like:

• really
• truly
• genuinely

In this sentence, really is the best match:

• This is not a lie; the bus really was delayed.

If you wanted a stronger sense of actually / in fact, Turkish might also use expressions like:

• aslında
• hakikaten
• gerçekten de

But gerçekten works very naturally here.

Because the two clauses are built differently:

1. Bu bir yalan değil
   This is a noun sentence.
   The predicate is bir yalan (a lie), so Turkish uses değil for negation.

2. Otobüs gecikti
   This is a verb sentence.
   The predicate is the verb gecikti (was delayed), so it uses normal verb tense endings.

That is why the structures look different:

• noun/adjective + değil
• verb + tense ending

Yes, Turkish often omits words that are obvious from context, especially pronouns, but nouns can also be omitted if the meaning is clear.

For example:

• Bir yalan değil. = It’s not a lie.
• Gerçekten gecikti. = It really was delayed.

However, in your full sentence, keeping bu and otobüs makes the meaning clearer and more natural, especially for emphasis.

A natural emphasis might be:

• Bu bir yalan değil; gerçekten otobüs gecikti.

The strongest stress often falls on:

• değil in the first clause, to deny the accusation
• gecikti in the second clause, to state what really happened

If someone were defending themselves, they might especially stress gerçekten:

• Bu bir yalan değil; GERÇEKTEN otobüs gecikti.

That gives the sense of:

• I’m serious—the bus really was delayed.

A few useful points:

• bu sounds like boo
• bir has a short, light i
• değil is often pronounced roughly like deyil in careful speech, though in fast speech it can sound smoother and more compressed
• gerçekten has a hard g as in get
• otobüs ends with ü, which has no exact English equivalent; it is like saying ee with rounded lips
• gecikti is pronounced roughly geh-jik-tee

You do not need perfect pronunciation immediately, but değil and ü are two places English speakers often need extra practice.

Yes. Depending on tone and context, natural translations include:

• This isn’t a lie; the bus really was delayed.
• I’m not lying; the bus really was late.
• This is not a lie; the bus really was delayed.
• It’s true—the bus was actually delayed.

Even though the Turkish sentence literally mentions a lie, English may sometimes translate it more idiomatically as I’m not lying, if that fits the situation.