circumfix（3）

In the lecture, she showed how en- -en functions as a circumfix that forms transitive verbs denoting an increase in, or intensification of, the quality denoted by the enclosed word.

Field linguists observed that the circumfix em- -en functions as a prebilabial variant marking causation in the dialect.

In the poem, the antiquarian pointed out uses of the circumfix a- -ing, noting how it once turned verbs into present participles and verbal nouns.