Animation parameter explaining

As a person who didn’t mastered English, it’s so hard to learn with animation’s parameter meaning.

I know there are three parameters for Animations.
They are fadeTime, weight and speed.

I know what speed does, but I can never know what fadeTime and weight does with AnimationTrack:Play()'s Wiki.

Can anyone explain it for me? If you can make a video is the best choice.
I will be so appreciated for anyone who answered me. Thank you!