Mr., Ms., Miss, Mrs. for ESL Students
The titles Mr., Ms., Miss, and Mrs. are often difficult for English language learners. And it's something so basic to native English speakers that ESL tutors and ESL teachers often take this for granted. Perhaps, I should speak for myself. I often take it for granted.
I usually notice that these titles are difficult for ESL students when they are reading aloud. This leads to an impromptu discussion about the pronunciation of each of these titles, as well as how to appropriately use them. (There's also an opportunity for a small reinforcement of the s/z distinction and voiced and unvoiced sounds.)
These titles can also lead to a mini-history lesson about the title "Ms." And even in how to address letters.
The two main points here are that for the ESL teacher or tutor, there are lots of ideas for lesson plans, and flexibility is important during a class.