can you recommend any (opensource or trusted) android apps to check who's using your wifi? or any cmd prompt code to search on the desktop?
a small doubt: can anyone hack your computer through WiFi? If so, How to prevent that (or) How to take measures after you think you been hacked?
Kind of, yes. If they use special characters and numbers, too, dictionary attacks would be far less useful. In the XKCD example above, something like this (Correct@Horse&BatteryStaple8) will be much harder with a dictionary attack. Definitely not impossible, though. Nothing is 100%.
I used to install and use foreign keyboard languages, but found it nearly impossible to use in some instances (bank sites, older iPhones versions, and so on).