I think your tree is shedding leaves it doesn't need in response to the heat. Trees often set more leaves in spring than they can support in summer. Locally, this behavior is more typical of later summer, but we've been having midsummer to later summer temperatures in June. And they came on abruptly. The speckles are remnants of chlorophyll, the green plant pigment.
Typically in these heat stress situations, the tree shuts down chlorophyll production in the "extra" or "unnecessary" leaves. Once chlorophyll production ceases the other pigments appear, which is why they are turning yellow.

Hi Mary, your response is interesting. I hope that is the case but my neighbors have the same aged crab apples and theirs look fine. Even today it lost a lot of leaves and is looking like fall. Thank you. 

It is always hard to determine why one tree is behaving in a certain way and others of similar age/type are not. It often comes back to some type of stressor.
I suggest you bring in an arborist to take a look at the tree in person. He/she will be able to look at the whole tree and see if there is some underlying problem that can be addressed.