I'm helping a friend learn English, and one of the things I like teaching is morphemes (parts of a word), by explaining the meaning of the morpheme and examples of it being used.
What resources are there for morphemes?
I tried using Wiktionary for looking up a morpheme (mono-), but when I tried looking up derived terms, it listed 504 examples, which isn't helpful, because most of the words aren't commonly used. The Online Etymology Dictionary has an entry about the morpheme, but doesn't provide examples. A search for mono was helpful, though searching for bi wouldn't work as well.
I came across Interactive Morpheme Dictionary, but "mon" only gives the examples "mononucleosis" and "monad", which aren't very useful as my friend is not a doctor or Haskell programmer.
It should provide examples of the morpheme which are commonly used. It doesn't need to provide definitions of the example words. Ideally the resource should be free.