CRJ-700 First Officer reported becoming task saturated during the descent and approach in an unfamiliar foreign country. The pilot states it was very difficult to understand the controller's instructions; the aircraft's path was directly into the sun; the haze and smog made visibility much worse; the pilot's aircraft configuration was initially incorrect for the position on the approach and the GPWS sounded because the aircraft was too low. The pilot reported the aircraft was stable by the FAF.

Narrative

Arriving into ZZZZ1 ATC left us high as we were getting closer to the airport. We descended with full boards deployed around 2500-3000 fpm descending out of FL290. As we started approaching FL200 we checked in with a new Controller in ZZZZ who had issued a change in the arrival; a new descent clearance and neither the PF (Pilot Flying) nor PF could understand what he was saying. We asked for clarification on what clearance was; eventually having us go direct ZZZZZ for RNP XX. When we read back the clearance he then told us to descent to 4;000 ft.; which seemed like it may work out; then he told us direct ZZZZZ1 for the RNP XX and cleared us for the approach. As we were leveling off at 4;000 ft. it was a 90 degree turn into the final course about 15 miles out. The sun was directly in our eyes disrupting our vision at this point. As we were slowing down and configuring they switched us to Tower; canceled the radar services and received a landing clearance form Tower. It was still very hard to see below us because of the direct sunlight; smoke and haze; while also being task saturated due to poor ATC communication. As I continued to configure and slow down; just prior to the final approach point I was about 200 ft. low. Captain verbalized this and GPWS called out terrain. I immediately clicked off the autopilot and leveled off and stabilized the aircraft. We got a 1;000 ft. GPSW call about 2400-2500 ft.; 1 mile prior of the FAF with the aircraft around 1800 ft. The aircraft is clear of terrain. I called for flaps 45 but it was a premature call as I still had boards deployed. At this point we had the runway; terrain insight and were about 7 miles prior to the runway; still prior to the FAF. I had the aircraft configured; stabilized and executed a normal landing. ATC left us high from FL290 and we became task saturated as the entire descent continued. We both found it incredibly difficult to understand his instructions. We were receiving changes in clearances one instruction after the other. I was adjusting speeds; altitudes; descent rates; multitasking the flying while trying to scan my eyes appropriately trying not to be blinded by the sun. Visibility deteriorated drastically due to the sun directly into our eyes once we turned final; smoke and haze also was a contributing factor. Unfamiliar airport also a contributing factor.I should have been flying the plane first and foremost knowing that the task saturation might continue well past the initial and middle part of the descent due to how high we were. The task saturation was derived from language barriers with ATC causing confusion on clearances. I should have asked for more time to descend and slow down instead of trying to squeeze it in. Perhaps asking for a hold or a 360 turn. I also should have scanned my instruments more effectively specifically my descent rate as we were slowing and configuring; while scanning instruments and outside references correctly; instead of trying to 'see around' the blindness. I will continue to build terrain into my briefs more effectively.