GIVE ANSWERS - English

Great definitions and I'll add something that I hope won't confuse you.
You might crumble a cookie to put it a mixture of ingredients (a recipe) (you can't say collapse here)
You might collapse on the couch when you're tired. (but you wouldn't say crumble here)

1. Collapse: it implies the somewhat abrupt and quick destruction, demise, or falling apart of a physical structure (building, statue, etc.), but also, in the more abstract sense, the (usually sudden and always decidedly resolute) "falling apart" of an agreement, an relationship, or the ruling power of a government, e.g., "The Soviet Union collapsed in 1991."

2. Crumble: usually implies a slow, deliberate falling apart -- decay even -- of a physical structure, but can as well be applied to more abstract concepts such as relationships between people, e.g., "Over several years their marriage crumbled."

Hope these explanations help/are clear, but if you require additional elaboration, don't hesitate to notify me.