I understand that this type of teaching is not used so much nowadays. But in what situations do you think it neccessary to teach formal grammar? This is a question in my TESOL course and although I have some ideas I would be grateful for some more that will help me compose my answer. Thank you.
As always, it's a matter of questioning the words used in the question; specifically -
What does it mean by "teaching"?
What does it mean by "formal"?
What does it mean by "grammar"?
At one end of the spectrum, the phrase 'formal grammar teaching' means encouraging students to think/discuss/internalize principles of how bits of language fit together, and at the other end the phrase means indoctrinating students with a set of prescriptive "rules". Loads of room for discussion there. No time for me to jump in though.