This is of course just obviously false on the face of it: if it were true, we could communicate more effectively with someone who spoke a different language but was face-to-face with us than we could with someone who spoke the same language, but via chat (or a blog post).
But those numbers are very specific to just have been randomly made up...
Here's where they come from:
According to pychcology professor Albert Mehrabian:
When you first meet new people, their initial impression of you will be based 55% on your appearance and body-language, 38% on your style of speaking and only 7% on what you actually say.Impression.
Now that actually makes sense! Not message. Not communication. Impression.
Furthermore, he was speaking specifically about communication about feelings, and the degree to which a person's non-verbal communication matched the verbal - as in, if a person says "I'm fine, really", but they look and sound upset, you are likely to not believe them.
In his own words, regarding this common misinterpretation of his work:
""Total Liking = 7% Verbal Liking + 38% Vocal Liking + 55% Facial Liking. Please note that this and other equations regarding relative importance of verbal and nonverbal messages were derived from experiments dealing with communications of feelings and attitudes (i.e., like–dislike). Unless a communicator is talking about their feelings or attitudes, these equations are not applicable."