Like Narcissus, each perceives the signs given by the other, but they cannot be sure exactly howto interpret those signs because they do not have any opportunity to talk about the significance oftheir gestures unless they find themselves in a private place. Narcissus notes that his reflection’sgestures mirror his own, but Elio and Oliver do not seem to realize that their signs of love arealmost exactly the same until they have the opportunity to speak about those signs. Nevertheless,in either case, it is the words that are missing: Narcissus needs his reflection to confirm withwords his suspicion that the reflection loves him back, just as Elio and Oliver both need spokenconsent from the other before pursuing their desire for each other.
Both of them echo each other's signs, and Elio does not understand himself enough to recognise his own reflection, projecting the same signs of affection he himself is giving off.
However, I disagree with the words argument. In my interpretation, words serves to confound the confession and true expression of identity, and what often gives it all away is the body. Just as the knight fuddles with words. Instead, Elio finds himself unable to refute the meaning his bodily expression brings.