Some people really just don't get this, either. And, VAK confusingly can be applied to preferred/natural communication style, as well as to preferred learning style. This tool is for preferred COMMUNICATING style. (for VAK learning style assessment see my previous post: Free Online VAK Learning Style Assessment)
It does ask you for personal details at the end, but I managed to proceed to my results without completing the fields or providing real information.
Give this link to the coachee: http://www.new-oceans.co.uk/new/lsdi.htm. Again I think the best time to do the assessment is in the morning, before work really starts.
When the assessment is complete, you will have the 3 in preferred sequence for communicating.
You now have material you can use to support the coaching goals and plans where guiding communication is required (100% of the time?). Once you are aware of your own preferred communication style, and your coachee's learning style, you can tailor what you say to be much more effective. And vice-versa, once you know your preferred learning style and your coachee's preferred communication style, instead of "shielding out" inadvertently some information you are sent by your coachee, you can be more aware to receiving, albeit in your non-favourite style! I find coaching relationships where we both know each other's preferred learning and communication styles much more fun as it allows us to safely practice new approaches on each other, to prepare us both for using these tools with others that we are having "problems" with. Really useful stuff!