ovladati

1. (a skill, language) to master
   Za godinu dana je ovladao srpskim jezikom. — He mastered Serbian in a year.
   Brzo je ovladala novim programom. — She quickly mastered the new software.
2. to take control of; to gain control over
   Policija je brzo ovladala situacijom. — The police quickly took control of the situation.
3. (of a feeling) to take hold of; to overcome
   Panika je ovladala putnicima. — Panic took hold of the passengers.

Takes the instrumental: ovladati jezikom, situacijom.