This isn’t a boasting post, although I’m sure it comes across as one on here.
My almost 19 month old can count objects 1-10. Today he did it on our walk, he counted 10 sheep poos! And when we got home he counted 10 objects from his tea set and then 10 books later on. This has all come on suddenly, but he can’t speak very well. Although he understands mostly all instructions I give him e.g. “can you please go and get your shoes” and most words.