Obviously chatter runs at one speed (normal for ATC). But the FO interactions are s-l-o-w as are the ATC instructions.

Is there any way to increase speed of speech?

Perhaps something outside of pilot2atc?

IF you're talking about the rate at which a voice speaks, on the Voices tab of Settings you can set the speed of each voice so the slow ones can be sped up and if you find a fast one, it can be slowed down....but I never saw one of those.

Dave