Question about simple negative sentences in Hebrew.
שלום!
In Hebrew is there an equivalent word to ليس and ليست in Arabic?
For example, is it correct to say:
מה זה? זה לחם?
לא, זה לא לחם.
Or do I need another word here - זה ___ לחם-
to make the sentence negative?
תודה!!!

Question

Question about simple negative sentences in Hebrew.
שלום!
In Hebrew is there an equivalent word to ليس and ليست in Arabic? 
For example, is it correct to say:
מה זה? זה לחם?
לא, זה לא לחם.
Or do I need another word here - זה ___ לחם-
to make the sentence negative? 
תודה!!!

Answer

If you want to say "this is not bread" you can simply write:
זה לא לחם
It's not mandatory to add the "לא" again in the beginning :)

Answer

Thanks Adi!

Answer

You should use the word לא, just like you did.  No need to use a different word.
 As for the remark that Noam wrote - You can use the first לא and you can use the sentence without the first לא.  It is just like in English.  If I ask:
What is that?  Is that bread?
You can answer it in both ways:
No, it isn't bread
or just
it isn't bread.
Personally I'll answer the exact same that you answered - לא, זה לא לחם
Adi