Can someone tell me how to classify the morpheme -ump, such as can be combined with lump,slump, bump, etc. (It's for a research I'm doing on onomatopoeia.) thanks
I don't see a morpheme or common word element in the three words. In my view ( different from etymonline) "lump" is connected with German Klumpen (with the same meaning as lump), "to slump" is connected with German plumpsen ( if you place the German s at the end in the position of the first English p you get slump), and "to bump" is connected to German bumsen (similar meaning). I can't discover that the three words contain a common word element.
Onomatopoeia means words that imitate sound. "lump" has nothing to do with sound. German plumpsen can be called a sound-imitating word, but after the s has taken the position of p at the front to give slump it is questionable whether "to slump" is sound-imitation.
I think "bump" is the only word where most people would agree that it is onomatopoetic.
Well, I think, the three words don't give much as to research in morphemes or sound-imitation.