Core and voice
Make a ambient_generic entity anywhere, give it a name, and make "SourceEntityName" the name of your core. Change SoundName to the sound you want to play.
And last, go to the core's outputs, add one. Choose "My Output Named" to be whatever, (OnHit, OnPlayerPickup, OnPlayerDrop, OnDeath, ect ect). "Targets entities named" will be the name of your ambient_generic, and the input is PlaySound. 
(Glados Lines
Wheatley
Cave Johnson
Caroline
Announcer
Defective Turret
Regular Turret
Cores)
portal2tenacious wrote:
Create an npc_personality_core and (assuming you want it to be Wheatley) name it @shpere. To male it talk, simply create a logic_choreographed_scene. Find the voice file from the scenes section and set everything up. The inputs should be pretty straight forward.
This
I don't do things very good when I find them out by myself.
Yenwood wrote:
My explanation was how I do it. :p
I don't do things very good when I find them out by myself.
You're not going to learn anything if you don't search and find out yourself (I know you said you fail but its definitely not true). I suggest you start at the vcd https://developer.valvesoftware.com/wik ... phed_scene. Someone was nice enough to make this page: https://developer.valvesoftware.com/wik ... aDOS_speak. That page would get you through the process of the logic_choreographic scene. Wheatley will be a bit different of course - refer to a reply above which states you use a npc_personality_core.
If you still aren't sure: decompile one of Valve's maps to see what entities they have in order to get wheatley to talk.
You could probably mimic this through some simple animations you can find out using the modelviewer and using an ambient_generic with a custom sound.