Questions & Answers about Chci ti zavolat večer.
Because the verb zavolat in this meaning takes the dative case (komu? – to whom?), not the accusative (koho? – whom?).
- Pattern: zavolat komu = to call someone (on the phone)
- Zavolám ti večer. – I’ll call you in the evening.
- Zavolám mu zítra. – I’ll call him tomorrow.
Ti is the short (clitic) dative form of ty (you, singular informal).
- nominative: ty
- dative: ti / tobě
- accusative: tě / tebe
If you used tě (accusative), the meaning would change:
- Učitel tě zavolal k tabuli. – The teacher called you to the board. (summoned you)
- pattern: zavolat koho kam – to call / summon someone somewhere
So zavolat ti = call you (phone), while zavolat tě is more like summon you physically somewhere.