Now NPCs can gain exp and most probably level up.

My question - The NPCs certain skills will rise when he level ups.It will be in accordance with *The Guide*?

For example - Foreign Language NPC

Diplomacy 1 2 3 (LVL 1 , 2 and 3)

So if the NPC gets lvl 2 he will have Dodge 2.
The owner of the NPC will most probably have the ability to assign additional lvl up skil points.If i assign my LVL 2 Foreign Language NPC a point(if i have 2 free) in Diplomacy so that he will have diplomacy 3, what will happen when the NPC gets level 3?Will it raise diplomacy by 4?Or will it leave it as it should be on lvl 3 = 3.

I believe NPC levels are different from XP levels that NPCs can gain. You should be able to assign the 1 skill point your NPC gains by levelling up to any skill you want it to have.

Yes, Hal is correct. You can assign available skill points to any skills.

I was pretty sure my second question would be misunderstood.my bad

I was asking what would happen on lvl 3if i assigned a lvl 2 foreign language NPC 2 skill points in Diplomacy so that the NPC would have Diplomacy 3.When it will be lvl 3 it should have by *The Guide* Diplomacy raised by 1 level automatically.What will happen if the NPC has the Diplomacy 3 skill on lvl 2 already?

Class levels are NOT XP levels.
The class level is decided on when the NPC is created, and doesn't change after that.

If you have a lvl 2 class level foreign language NPC then it will never be a lvl 3 class level foreign language NPC. At lvl 3 you will have a class 2 level 3 foreign language NPC with 2 points in diplomacy, and two skill points to spend for xp level 2/3.