The issue was, and still is, hotly debated at the grass roots level, with children coming to our schools speaking more than 200 languages.
In the above sentence, I guess the subject is "issue" and the predicate is "was/is". "hotly debated at the grass roots level" is used to embellish "issue". And I'm confused by "with children coming to our schools speaking more than 200 languages". Is the object "with children coming to our schools speaking more than 200 languages"?