What’s the difference between the terms L2, ESL, multilingual, etc?

I don’t speak my students’ native language(s). What do I do? 

I don’t know how to explain grammar. What do I do?

I’m not sure how to evaluate my L2 students’ written work. What do I do?

Wouldn’t it be better to let a language expert tutor my L2 students or “fix” their written work for them? 

Why can’t Word’s “grammar check” feature or software like “Grammarly” fix L2 students’ grammatical errors and unusual sentence structures?

This answer is straightforward enough to include here! Namely: artificial intelligence cannot (yet – maybe ever?) process language as effectively as humans process language. AI often cannot make sense of the following features of language: extended noun phrases that function as the subject of a sentence; embedded clauses; the transitivity of a verb (whether or not the verb needs an object and, if so, what kind of object); rhetorical conventions; appropriate use of determiners, such as “the,” “a/n,” “many,” “these,” “none,” and “our;” the context of a piece of writing and the way that words or sentences “fit” into the overall picture of a text; and cultural norms governing the use of language. As long as AI remains unable to process such features of language use, grammar check programs will be unable to help students with all but the most basic errors.