Well, we are creatures of habit. The words we use are a prime example. Habits of speech will impact greatly on what is said by our inner voice.
We may speak words of significance for many different reasons, different sides of an argument (a multi-tasking)...
I think the inner voice and what thought is are closely related. They are different ways of reacting expressively to a different sensation; whether it be having something to express in words (inner voice) or a way of preparing perception to 'see' something in particular or to act in a particular way (thought)...
Knowledge as I see it, is 'to know to do something (in a given situation)' or 'to react in a particular way (giving rise to associating around a situation)'.
As for the emotion involved ... this is a lot like the pleasure and pain , laughter and tears, smile and frown, encouragement and discouragement deal... it adds a lot of feeling that has context.
In fact it is what makes or breaks context from the words, preparation and knowledgeable actions used...
The inner voice can be 'silent', the thoughts may be so general or peace-giving that they're 'melting' and actions either 'still' or 'fluid', such that you can be one with what feels empty, with what feels to be like nothing, where there is no context and less emotion...
Does that sound right to you?