The captain’s rotation of the airplane pitch before the rotation speed on takeoff due to his surprise about encountering head on landing traffic, which resulted in an exceedance of the airplane’s pitch limit and a subsequent tail strike. Contributing to the accident was the flight crew’s expectation bias that the incoming aircraft was landing on the same runway as they were departing from, and the conflicting traffic’s nonstandard use of phraseology when making position calls on the common traffic advisory frequency.