I knew the language of the floweret; (5)
This could mean that the speaker knows the flower's language because women are closer to nature than men. Since the rose is pure, and women are closer to flowers, the speaker suggests that… women are purer than men. Or, it could mean that, since she gets them like all the stinkin' time, the speaker is really familiar with the whole flowers = love routine.
Why is it no one ever sent me yetOne perfect limousine, do you suppose? (9-10)
The limousine is important because it suggests mobility. The speaker's desire for something that can move her suggests something about the confinement of women in the early twentieth century.
Ah no, it's always just my luck to getOne perfect rose (11-12)
It's not just the speaker's luck, it's all women's. The speaker hints that there is something offensive about the fact that women only ever receive flowers, instead of cooler things like limousines. Don't they deserve cool stuff, too?