Learn French: Le porte-parole dément formellement la spéculation infondée. - The spokesperson formally denies the unfounded speculation.

It comes from the verb démentir, meaning "to deny" or "to refute." It conjugates just like mentir or sentir (e.g., je démens, il dément, nous démentons). Be careful not to confuse it with the adjective dément (meaning insane or wild), even though they look identical!

Can porte-parole be feminine if the spokesperson is a woman?

Yes! It can be either masculine (le porte-parole) or feminine (la porte-parole) depending on the person's gender. Also, because it is a compound noun made of a verb (porter) and a noun (parole), it is invariable in the plural: les porte-parole (literally, people who "carry the word").

Does formellement just mean "in a formal setting" here?

It carries a much stronger meaning than the English "formally." In French, formellement is often used to mean "categorically," "strictly," or "expressly." Démentir formellement is a very common phrase meaning "to categorically deny." You will also often see interdire formellement (to strictly forbid).

How could we express a similar strong denial using this lesson's grammar point (ne... aucunement or ne... nullement)?