Children with expressive language disorder have difficulty conveying or expressing information in speech, writing, sign language or gesture. (For preschool children, the difficulty expressing themselves in writing is not evident, as they have not started formal education.)
Rectangles have longer sides than any type of square. Opposite sides of rectangles are of equal lengths. All sides of squares are of equal lengths. Rectangles have longer sides than any type of square. Opposite sides of rectangles are of equal lengths. All sides of squares are of equal lengths.
A rectangle is a special case of a parallelogram. All rectangles are parallelograms. But a rectangle is a shape where opposites sides are parallel *and* all the corners are 90 degree angles. So you can't say that all parallelograms would be rectangles. Some parallelograms would be rectangles, but not all. Rectangles are a subset of the shapes called parallelograms.