The dictionary defines collusion as ‘secret cooperation between people in order to do something illegal or underhand’. Collusion in coaching is bit less sneaky, but it does involve some kind of avoidance when you sense an area that's uncomfortable. As coach, you may be hesitant or fearful to say what you're thinking because of the potential impact on the client. Or you may pick up on your client's hesitance to break a pattern.
By listening carefully to a client's voice, you can glean lots of useful information, particularly about topics that you and your client may be avoiding. After you identify the collusion, you can courageously intrude and break a pattern.
The voice has a powerful and often overlooked role to play in coaching. Richard Bandler, the co-creator of NLP, has suggested that everyone should have a voice coach. The history of NLP is rich with great teachers who use their voices with masterful flexibility, notably Milton Erickson, the late hypnotherapist and more recently one of Erickson's students, Stephen Gilligan.
As a coach, you can develop and use your own voice as an invitation to communicate at different levels – with lightness, warmth, humour and all manner of appealing qualities. When listening well, you also gain a huge amount of information from the client's voice.
In her excellent book Voice of Influence ...