True or False?
The Romans had no word for “yes” or “no.” They did, however, have three ways to ask a yes or no question! Lacking a simple yes or no, gestures, head bobs, or head shakes were used (not all language is verbal!). One could also repeat whatever was in question with or without negation.
The word you may associate most with “yes” in the Romance languages is si. Si is from the Latin word sī -c, “just like that.” English also has a ghost of the old Latin sī -c. You see it in square brackets after the quotation of an obvious gaffe that a news reporter doesn't want to take blame for (e.g., “Bush said not to misunderestimate [sic] him”).
You have already learned the enclitic -que. It means “and” (in a special way), and, as an enclitic, cannot stand on its own. It is a syllable that needs to be attached to the end of another word. The enclitic -ne works in a similar fashion. You can attach -ne to the end of the first word of a sentence and instantly convert it to a yes/no question. Shifting word order shifts emphasis.
Tū mē amā s. (You love me.)
Tū ne mē amā s? (Do you love me?)
Mē ne amā s? (Do you love me?)
Amā sne mē ? (Do you love me?)
The interrogative adverb nī nne also poses a yes/no question, but it baits the answerer for a yes.
Nī nne mē amā s? (You love me, don't you?)
If you pull nī nne apart you will see that it is actually just nī n with -ne on the end. It essentially makes nī n into a question. “You love me. No?”
The adverb num does the opposite. It expects a “no” answer.
Num mē amā s? (You don't love me, do you?)
The word num is most often seen in the sense of the English word “whether.” “Whether” suggests a sort of conditional situation where the outcome is doubtful. Latin takes this dubious situation to a more pessimistic end: “(I don't know) whether you love me (you don't, do you)?”
What is the origin of the question mark?
The Romans did not use punctuation. Using dots and squiggles to tell you how to read did not occur until the Middle Ages. The question mark is an elongated Q, standing for the Latin word quaestiō (“question”) set on top of a period.

