Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Confusion; Situational Awareness
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued Advisory / Alert; Flight Crew Requested ATC Assistance / Clarification
Human Factors
On the taxiway contacted Tower.  After check in we thought we heard 'clear for takeoff;' but neither of us were sure so I asked the First Officer to confirm if we were cleared for takeoff. The First Officer asked this question and the very clear reply was 'affirmative.'  We entered the runway and were subsequently told while finishing our line up on centerline to stop and hold position.  After a delay we were told of 'pilot deviation' and then cleared for takeoff.I allowed an 'affirmative' reply by Tower to suffice for a query on were we cleared for takeoff.  That is the root cause.  'Affirmative' is not the correct response and in retrospect I believe Tower perhaps misunderstood our query.  Choice of words and insistence on clarification.  I should have asked the First Officer to say 'Tower say again.'  Tower would then have repeated all instructions.  Looking back the word 'Affirmative' is not enough.  I allowed my leeway on foreign controllers English and accents to accept 'affirmative' for a cleared for takeoff query rather than insisting on hearing the entire standard 'cleared for takeoff' verbiage. The Tower could have easily misunderstood us and replied 'Affirmative' to what Tower believed was the question.
Air carrier Captain reported confusing communications regarding the takeoff clearance resulted in ATC advising them they departed RCTP airport without a takeoff clearance.