Answer:
The three main words in the English language that begin with 'dw' are dwindle, dwarf and dwell. Of course, there are others, but they all build on those three - dwindling, dwarfish, dwelling, dwarfed, dwarfs, dwarfism.
Oh, and just for the record I think that the word dwarfs should be dwarves, and the word dwarfish should be dwarvish, but that's just me. Dwarfism should be dwarvism. I also think the words elfin and elfish should be elven and elvish. It looks better.
By the way, in case you're wondering, dwarfism refers to being a dwarf or being dwarfed.