How do I get rid of the "echo" of audio "speaking" files during game play?

I have recorded some MONO, 16 bit, 8000Hz talking files. When I reach an AI and they say the “speech”, there is a terrible echo. I did not record an echo. I played them back OFF GAME and they sound clear.
Any settings in UNITY to cut out this echo?

As long as your speaking event is triggered by a collider entering trigger collider and your AI-object has two colliders, the event occurs twice.

Because you are using ‘AudioSource.PlayClipAtPoint’ instead of ‘AudioSource.Play’, there are two sounds played, the delay between them is equal to delay between first and second colliders entering the trigger.

So what you should do is to put your trigger collider on AI-object in another layer and adjust Layer Collision Matrix to make sure that this layer does not interact with your speaking event’s trigger. To figure out how it works take a look on Layer-Based Collision Detection.

At least try to read the Manuals, watch Tutorials and understand what you are doing! Good luck.