I just met my neighbor for the first time. We had two conversations in the space of five minutes. The first was prompted when we both walked out of our apartments with cell phones in hand trying to figure out why there were warning/air raid sirens going off.
When I heard the sirens I thought, "OK, let me look outside and see what the locals are doing." So, I poked my head out the window and then realized that was useless and potentially stupid. As I opened my apartment door to see if anyone was heading down to the מקלט/miklat/bomb shelter, I met a neighbor I had never seen before. She had clearly just thrown her coat on over her house clothes; she had two phones and her wallet. She asked me if I knew what was happening and I asked her the same and my immediate thought was, "I don't remember how to say, 'siren!!!'" But we communicated. The sirens stopped while we were wondering what to do. She headed back to her apartment and said, "Good, I hope I don't see you again in a little bit." I agreed but asked that if she figured something out, to please tell me.
I came inside, looked up "siren" and found the local radio news online. They said that sirens had been heard in many neighborhoods in Jerusalem (the word they used for "siren" was not any of the five options the dictionary had given me) and that they did not yet know what was happening but they would tell us as soon as they knew. Then, after the rest of the news (the dead in Gaza, rockets in Ashkelon, and more rockets from Lebanon) they said that we should all relax in Jerusalem and return to our routine because it was just a תקלה/takala/a mishap, a fault, a hitch in the system's giddy-up, nothing was going wrong in Jeruaslem.
And then my nieghbor knocked on my door to tell me the same news. Not to worry.