What are expressive adverbs?

Actually, this does not seem to be a common expression in English, but rather, in some foreign languages. In English, adverbs are simply Words that are used when describing (modifying) verbs. An example: the boy ran quickly down the street. The verb is "ran" and the Word "quickly" describes how he ran. Another example: The teacher responded patiently to the student. The verb is "responded" and "patiently" describes how the response was given. When writing, it is always a good idea to be expressive-- to use descriptive Words that clearly illustrate the points you are trying to make.

However, the term "expressive adverb" seems to refer to a certain type of adverb in one of the languages of Burma-- these Words not only describe (modify) a verb but may be derived from that verb. I enclose a link to a grammar book of the Kham language, which gives examples of this time of adverbial construction.