We as teachers try to solve every problem but often we miss things. This video shows how easy it is to get wrapped up in one thing and completely miss something else.
In the case of the video, we were so focused on the budding romance that we didn't look behind to the other people on the screen. While this was done through creative video editng, our brains do the same thing in the classroom. It's much easier to pay attention to the hyper student running around than the shy student starring out the window.
When dealing with language learners, this is sadly even more possible. The language barrier might cause a teacher to miss critical signs. Not just for extremes such as suicidal violent behaviors but also in the smaller situations such as understanding the class material. The cultural norms can also play a part in these situations. In some cultures, it's frowned upon to ask questions.
To help prevent things from falling through the cracks, we can create an anonymous ways for students and parents to report suspicions. A Google Form with just a small comment section can allow students to send concerns to administration without any identifiable information. Students often want to help but are scared of retribution. This actually happened recently in my class. I received an email from a parent expressing concern. Her son had apparently heard a classmate make suicidal comments last month but was too scared to tell anyone. She emailed me after he broke down and told her but said he begged to keep his name out of it. I passed the information along to the proper people but this was a month where we could have been productively trying to help the student but none of the teachers were aware of the situation.