1- Insert required display text in the URL, just like that:
http://bavardages-timer.clucien.com/?text=Taisez-vous, je vous prie.
2- Click 'Start', and wait for chatters to stop.
3- You may hit 'Pause' when they're done.
4- You now have recorded the exact duration of the undesired natters, and you may use the information freely.
5- The End.