In an ideal world, feedback would always happen face-to-face, so the other person could read your body language and hear your voice. But there are times when you have to provide input through email, text message, or even instant message, and in these cases it’s important to be careful about tone. Written criticism can easily lead to misunderstandings, since it’s missing the natural empathy that comes from talking to someone in person. And once it’s typed, it’s harder to take back than a spoken comment. Generally, your written feedback should stick to descriptive, rather than evaluative, language. People are usually more receptive to, for example, “This is what I see happening” than to “This is what I think you should do differently.” The latter can be read as harsh and uncaring, whereas the former is more objective. You’ll have more latitude if you have a strong relationship with the recipient, because the person is less likely to perceive the criticism as an attack. Still, the extra effort you put into thinking through what to say and how to say it will help the person hear your message (even if they’re reading it).
Source: Adapted from “What I Learned About Coaching After Losing the Ability to Speak,” by Mark Rosen