Saltēre Saltō ( dance, jump, dance portrayal, pantomime ) • of Saliō • Saltus ( leap, jump ) • English Sally ( sortie ) • French Saillir leap forth • Latin Salīre
Soleō Saltāre accustom, tend
Usually acts as a verb in these sentences?
In the Latin, yes. The verb solēre means 'to be accustomed to', 'to tend to', 'to be in the habit of', etc. That is where Duolingo is getting the 'usually'.
"I usually dance by night" isn't allowed for some reason...