A little background: my employer has a client and this client is pretty big and they are using the system for many users and I'm the only resource person who knows the source code and everything in it. The first few months was fine and I receive my salary on time. They told me that they were having problems with the finance recently but I'm skeptic because they hired another contractual developer to do other work for them.
So I've been working for this employer for more than a year now but they keep on delaying salary and currently 2 months delayed. I already have deployed the project in the development sites for testing purposes and there are items that still need fixing and other features to be added along the way. My question is, should I keep on working with this employer or should I tell them that I need to get paid first before I resume work? I'm not the kind of person who does things demandingly.
Key Question
So what should be my tone of voice? Inquiring? Demanding? I don't like to put bad impressions on clients/employers and burn bridges.
Also I'm thinking my employer might lose this client because of me not proceeding but I need to get paid first, I have a family to feed. By the way, the system was worked by a different developer primarily and I just took over and my employer just got hold of the codes with which they don't have idea how to so I'm the one managing it at the moment and currently under my Git account.
Update
So my employer paid me already but it took more time than I have expected. It just takes patience and lots of it and had to remind them a couple of times. So lesson learned, make sure you are getting paid (at most) every fortnightly so if in case your employer won't be able to pay you at least the damage will be manageable to a minimum. Nevertheless, just be honest as much as possible with your dealings regardless if your boss is not. In the end it's not your loss but theirs.