B.B.
I wonder if it could be teething. My DD is typically a delightful child, but between 1 and 2, she would get grumpy whenever she cut a tooth. Tylenol and orajel helped a bit, but she was irritable until the new tooth broke the gum. Every child is different though, my son now doesn't show any symptoms of teething and a new tooth just came in. I also think around 16 months they comprehend so much but are unable to express themselves verbally and that can be frustrating to them. Good luck! In time, she will outgrow the phase. They grow up so fast. ;)