Most Sylvans (also commonly called "Elves") that interact with other races are Grey Elves--not so much a separate race, but a distinction for those that have adopted many human ways. More rare are the "Deep Elves," who avoid interracial contact altogether.
Grey Elves have coexisted with other races for centuries, but still prefer forest settings to cities. Sylvan look like short, thin Humans.
Sylvans are known to easily blend in with their surroundings.
Their native tongue is Ilsardinish.
Note:the plural of Sylvan is Sylvans, not sylvi.