Learn Hardcore Turkish: Ben ona el sallıyorum.

It’s optional. The verb ending in sallıyorum (-um = “I”) already shows the subject. Using Ben adds emphasis or contrast, like “I’m the one who’s waving to him/her.”

What exactly does ona mean here?

Ona is the dative form of o (“he/she/it/that”), meaning “to him/her/it.” Turkish pronouns are gender‑neutral, so ona can mean any of those depending on context.

Why is it ona and not onu?

Because the verb phrase el sallamak (“to wave [a hand]”) takes a dative target: you wave “to” someone.

ona = to him/her/it (dative) → correct with el sallamak
onu = him/her/it (accusative, direct object) → would mean “I am shaking him/her/it” with sallamak, not waving.

Why do we need el? Can’t I just say sallıyorum?

On its own, sallamak primarily means “to shake/swing.” To specifically mean “to wave,” Turkish uses the light‑verb compound el sallamak (“to wave [the hand]”).

Sallıyorum by itself implies “I’m shaking (something)” and normally needs a direct object (e.g., Onu sallıyorum = “I’m shaking it”).
El sallıyorum = “I’m waving (my hand).”

Why isn’t el in the accusative (eli/eli̇mi)? Why not elimi?