Tone is what determines meaning, the vast majority of the time. There is an amusing advertising campaign right now, for insurance I think, depicting two people saying exactly the same thing, but in different contexts. If watch those ads with your eyes closed, so you hear exactly the same words without any visuals, you will still assign a totally different meaning to what is being communicated by each speaker; you don't need the visuals. In fact, tone is so highly determinative of what is intended, I wonder about the use of transcripts for any important purpose. The idea that a transcript is somehow better, because it is a record of only the worlds used so it is objective, is completely wrong, IMO. Even the simplest phrase, such as "Oh my gosh, this is great!" could just as easily be full of joy or full of sarcasm. Unless you hear it spoken, hear the tone, you may be entirely wrong about what was intended. We have all written emails which were read by the recipient with a different tone than what we intended when we were writing it. You are undoubtedly assigning a tone to this as you read it!