Bil’am tells Balak to build altars and he leaves to call upon Hashem. Hashem tells him to return to Balak VECHO TEDABER, “…and thus you shall speak”. (Num. 23,5) Although Hashem puts the words into his mouth He does not say “this you shall speak” but “thus you shall speak”. The reason is because when people talk it is not only the words that count but also how the words are said.
For example, Bil’am said: MAH TOVU OHALECHA YAAKOV. This can be said as a statement of praise or it can be said in the form of a question which would imply just the opposite. What purpose does it serve you? That is why Hashem told him exactly how he should say the words. “Thus you shall speak” so there would be no misunderstanding.
When politicians speak, when teachers speak and when we speak we must be very careful to speak with the correct inflection and intonation in order to relay the proper nuances we wish to convey.