"Скажи, ты пьёшь молоко."

Translation: Tell me, do you drink milk?

[JuvenW]

How to compare

"Скажите, вы пьете молоко?"
vs

"Скажи, ты пьёшь молоко?"

What are the differences in meanings?

[ddmits]

Is a question mark missing here?

[Shady_arc]

Yes. That was unexpected. Removed this sentence.