I agree with fluttermoth. But with a sword plant, here Echinodorus griesbachii [may be encountered as E. bleherae or E. amazonicus], it will likely send out an inflorescence, which is a flower stalk. But when grown submersed, the nodes along this inflorescence will not flower but produce adventitious (daughter) plants. Once they have sufficient roots and leaves, they are easy to pull off and plant as new plants.
Sometimes it takes a while before a plant will do this. It depends upon the water, light and nutrients, and the age of the plant. And the plant's internal life cycle. I have noticed that my many plants of several species have definite cycles, corresponding with the seasons in their natural habitat, but these are largely retained in aquarium cultivation.
Byron.