No, no, no, the timer definitely needs to be increased. There is currently only a few seconds between the same set of sentences, both in the chat and with the voice overs, leading to major audio and visual spam.

This is so annoying that I had to mute the voices after a few minutes in Cyseal. Please create a timer of at least 1 minute between repeating the same set of sentences. Otherwise it's a major break in the immersion. The voice overs must have really been rushed in for such an annoying problem to be overlooked.

There are some good ideas in this thread, but the frequency of the NPC voice overs should really be the main concern, as far as audio goes.