This is the 2460th most frequent German word.
schwierigkeit
Difficulty; problem.
Here, 'Schwierigkeit' is used as a noun in its singular form to describe the challenging nature of the task.
Die Schwierigkeit dieser Aufgabe liegt in ihrer Komplexität.
The difficulty of this task lies in its complexity.
In this sentence, 'Schwierigkeiten' appears in its plural form, indicating multiple or ongoing challenges that the subject is facing.
Er hat große Schwierigkeiten, die neue Sprache zu lernen.
He has great difficulties learning the new language.
Here, 'Schwierigkeit' is used as a singular noun that metaphorically represents an obstacle one is encouraged to tackle.