What do you find the hardest about learning other languages?

purplepoppy
Some people pick up languages easier than a drunk slut picks up guys, but for most people they don't come easily. So if you're learning a new language or perhaps already know another one, what part of getting to grips with a new language do you find the most difficult.
The writing system
The grammar
The pronunciation
Idioms/sayings
Dialects and accents
Select gender and age to cast your vote:
What do you find the hardest about learning other languages?
20 Opinion