Good work on the students' part. I had a student look up "explicate" on a smart phone where we discovered the definition: "analyze or develop an idea in detail."
So I asked, "If we have a perfectly good word like 'explain' that everyone understands, why do we need the word 'explicate'?"
One brave student volunteered, "So we can sound more sophisticated?"
I said, "Say more about that."
"You know, so you sound like an educated person."
"So if I said, 'Allow me to explicate tomorrow's homework assignment', I would sound more sophisticated?"
"Well, actually, you just sound silly? It sounds like you are trying to use a big word."
"Right, so why do we have a word like explicate?"
Another student jumped in, "From the sentence, it sounds like 'explicate' is a more involved explanation."
"Good," I said, "Now why do we need both 'explain' and 'explicate' in our vocabularies?"
"I guess we have these similar words in our language so we can be more specific when we speak"
"Bingo!" I said, "Not only when we speak, but when we write. One sign of an educated person is a person who has the vocabulary to use just the right word to communicate a thought."
I tell you this story because I think it is illustrative of what we need to consider when we teach vocabulary. Just as in reading comprehension, where we activate background knowledge to help readers understand what they are reading, so, too, in vocabulary instruction, we use what students already know about a concept to build new knowledge in the form of new and more specific words.
Allow me to, ahem, explicate.
All of the students in my class had a concept for "explain." To help them learn the word "explicate", I needed to tap into that "explain" concept to help them make the connection to the new word "explicate." We came away from the lesson, I hope, with the understanding that explicate was reserved for rather involved explanations of complex ideas.
Let's consider how this operates with very young children. My 2 year-old granddaughter Schuyler lives in a house with two cats. The first time she saw one of our dogs, she pointed and said, "Cat." Schuyler had a concept for pet (four legs, tail, lives in the house with people) but it was not yet sophisticated enough to see the nuances of dogdom (barking, tail wagging, different kind of fur). After a few exposures to dogs and other household animals, Schuyler had expanded her concept of "pet" to include dogs, birds, fish and other animals.
Now let's move this insight into the classroom. Whenever we are trying to teach new words to children, we must first prepare them to receive the new word by tapping into the already existent concept. Kids have a concept of anger, so if we want to teach the word "livid", we would first ask them to generate words that they associate with anger (mad, angry, unhappy, furious, annoyed, enraged) and then ask them to place these words on a continuum of anger, perhaps from unhappy to furious, and then locate "livid" along that continuum somewhat closer to furious than unhappy.
Here is another way to bring context to bear on vocabulary learning. In the "In the Box, Out of the Box" strategy, students are asked to provide words for a concept they already know. In the example below the concept is "the person who is in charge at the local convenience store." Both words that fit the concept,"in the box", and those that do not, "out of the box", are listed and then the target word "proprietor" is added to the box to show how it fits with the concept. Note that both words that fit the concept and those that do not (cashier, worker) help us to define the concept.
Literacy researchers Nell Duke and David Pearson say that words are not the point of words - ideas are. Ideas are concepts and as we guide children toward more sophisticated vocabulary, we are guiding them, not as my college freshman would have it, to sound more sophisticated, but to more sophisticated ideas, and ultimately toward more sophisticated thinking. You may be able to think a thought without a word for it, but you can't share that thought with others, verbally or in writing, without having the right word for the idea.
The effective teaching of vocabulary, is quite literally, teaching children to think with greater sophistication.