The talker may react as he or she does because of nervousness, a lack of self-awareness, or out of a desire to show off (Jacobs 2012: 377). To restrain a chronic talker, a leader can stress that he or she wants everyone to respond to a particular question or specifically ask members of the group to respond who have not yet spoken (Jacobs 2012: 377). Leaders can also provide individualized feedback in a written form so as not to embarrass a 'nervous' chronic talker and to enable him or her to become more self-aware. The 'dominator' type likes to control the group not only by speaking a great deal but also with the force and vehemence of his communication. He may try to take control of the group session....

However, in some extreme instances, it may be necessary to ask the dominator to leave the group (Jacobs 2012: 377). Distractors must likewise be dealt with firmly, redirecting the comments to the purpose at hand, and refusing to allow them to set the agenda. Often the best way to deal with a distractor is the same way to deal with group silence: asking on-point questions that require a focused answer.
References

Forsyth, D.R. (2014). Group dynamics. Cengage.

Jacobs, E. (2012). Group counseling: Strategies…