ספּר
The root word for “message” is ספּר 'ceper'.
In many cases where the word “message” appears in the English Old Testamant translations, there is actually no corresponding word in the original Hebrew text. The translators simply assumed from the context that a message was being sent. In general, not a bad assumption, but specifically, terrible practice when it comes to direct translation. A few such examples of this practice are in:
In other caser, the work melak is erroneously translated as “message” or “messenger”