Signal je dobar.

Je is the 3rd person singular present form of biti, which means to be.

So in Signal je dobar, je is the word is.

• signal = signal
• je = is
• dobar = good

Serbian does not have articles like a and the.

So signal can mean:

• a signal
• the signal

The exact meaning depends on context. In English, you have to choose an article, but Serbian usually does not mark that difference directly.

Because adjectives in Serbian must agree with the noun in gender, number, and case.

Here, signal is:

• masculine
• singular
• nominative

So the adjective must also be masculine singular nominative:

• dobar = masculine
• dobra = feminine
• dobro = neuter

That is why Signal je dobar is correct.

A very common pattern in Serbian is:

• nouns ending in a consonant are often masculine

Since signal ends in -l, it is masculine.

This is not a perfect rule, but it works for many nouns.

It is in the nominative singular because it is the subject of the sentence.

In Signal je dobar:

• signal = subject, so nominative
• dobar also matches it in nominative singular masculine

So this is a basic subject + to be + adjective sentence.

Because je is a clitic in Serbian. Clitics usually go in the second position of the sentence or clause.

So:

• Signal je dobar = normal neutral order

If you move another element to the front, je still usually stays second:

• Dobar je signal = also correct

That second-position behavior is very typical in Serbian.

Yes. Dobar je signal is also correct.

The difference is mainly emphasis:

• Signal je dobar = neutral, straightforward
• Dobar je signal = puts more focus on good

Both mean essentially the same thing, but the information focus changes a little.

Yes, but that is not a full sentence.

Dobar signal means a good signal or the good signal. It is just a noun phrase.

If you want a complete sentence, you need je:

• Signal je dobar
• Dobar je signal

Normally, in a full standard sentence, no.

You should say:

• Signal je dobar.

Leaving out je would usually sound incomplete, unless you are using a fragment, a note, a headline, or very informal shortened speech.

So for learners, the safe rule is: keep je.

Yes. Signal is a normal Serbian noun, borrowed from an international word, and it is fully used like a Serbian masculine noun.

For example:

• signal = nominative
• signala = genitive
• signalu = dative/locative
• signalom = instrumental

So even though it may look familiar to an English speaker, it still behaves like a regular Serbian noun.

You replace je with nije:

• Signal nije dobar. = The signal is not good.

This is the normal negative form of to be in the present tense.

A few common ways are:

• Da li je signal dobar? = Is the signal good?
• Je l' signal dobar? = Is the signal good?
  This is more conversational.
• Signal je dobar? = Is the signal good?
  This can work in speech with question intonation.

For beginners, Da li je signal dobar? is a very safe and standard pattern.