Despite variations in language acquisition,, there is a certain pattern visible in spoken language acquisition.
Some types of words develop first and only then others do, and some patterns in word formation keep reoccuring.
There aren't any compound words either, at first. Not until later.
You see the same developments in sign language. Signs aren't produced completely correctly at first.
Signs don't have the right shape of the hand and complicated shapes don't come until later.
So this development is the same in both sign language and spoken language.
You see that in the development of grammar as well.
More complicated forms like grammatical facial expressions aren't developed until later.
So development in sign language goes through the same steps as in spoken language and it isn't more difficult either.
It's simply language acquisition. Whether it's spoken language or sign language. That doesn't really matter.
My two children are now five years and seventeen months old. They're both hearing children.
I'm deaf myself and my husband is hearing. Our children are learning both languages at the same time.
The development of vocabulary and sentence structure is developing at the same pace in both languages.
It's not difficult for them at all, they develop at a similar pace.