Unless he is painfully shy, he should be a little chatterbox at that age, for sure.

My son is 3 old and talks all the time, sometimes we have no clue what he’s trying to tell us😊 but he has 4 older siblings and therefore gets a lot of attention and stimulation. I would say he’s at the advanced stage for his age. If he wasn’t the youngest, he probably wouldn’t learn as quickly. He’s also quite lazy when he wants to be. He can walk but more often than not wants to be carried. That’s the down side of being the youngest - a lot more people around to carry you! Crying isn’t unusual and doesn’t mean they’re unhappy. Until they can be properly understood and effectively communicate, they will cry more, it’s their form of expression. My son cries often throughout the day and it is exhausting at times. Even when parents know the right thing to do, we do get to the end of our tether. The concerning part is that he walks off and they don’t appear to know he’s gone. Luckily you’re a caring neighbour but he could come across a paedophile or someone wishing him harm. That’s not good at all. They may be overwhelmed parents, as so many of us are these days

First words are often uttered as young as 12 months, or as late as 18 months. Babies start to crawl at about 7 months. The very latest a child will learn to walk will be at about 18 months.

Potty use is between 18 months and three years.

My parents friends had a third child who was developmentally delayed. His mother never dressed him, and he was much slower in development than the family's other children.

Interesting question. I would say that a kid at 2,5 would normally walk, run, play, talk, ask questions like little kids do. At least that's how it was with me, my brother, cousins...

He might also have special needs plus he is a toddler

There all different. There no rule book for what happens when. :)