I am a person with a large vocabulary (in English)
I tend to use larger and more pretentious words because I like the way they sound and it's my humor. Words like rebuttal, amiable, quite, sustainable, appease able in my regular day to day conversations.
However with all this in mind, if I know another person has English as a second language AND are still learning, I would not hesitate to use a much more common vocabulary. If they are really new I would slow my speech, enunciate the important words and use basic sentence structure. To me this is common courtesy. I wouldn't assume by an accent or anything but, most of the time this works well.
Now, what I cannot for the life of me understand is how it is more acceptable for me to do this to a Child than a new English speaker.
I have had people ask me to not use bigger words around kids because they don't understand but those same people will mock those who are struggling with English. I do not get it. Kids need to soak in words. I got a large vocabulary by soaking it in from the adults around me.
Bottom line: kids need to be exposed to a large vocabulary. Adult foreign language learners are already trying as hard as they can, cut them some slack










