You can pretty much think of emotional states as finite state machines with n! states, and n is at least 100. Ultimately, the problem is that you can, while feeling one already complex emotion, simultaneously feel another extremely complex emotion. This layering can happen n - levels deep.
So, not only can you have happy at a friend's wedding vs happy at the funeral of a friend who's no longer battling cancer and is free from pain (as @Green mentioned), but you can simultaneously feel guilty at feeling happy, and feel the pressure of responsibility from your own family, and feel... etc. etc. etc..
So, to be able to describe an emotional state, you can't simply use an IPA-like dictionary to map emotional state-to-words, what you need is the building blocks to be able to compose multiple emotional states which are then composable with each other. At which point, what you're asking for is an international language standard. Welcome to Esperanto.
be incredibly useful to writers, programmers, psychologists
, yes. That's the ideal state for any language or art form in general; and like any other ideal, sadly unattainable. – nzaman Aug 17 '16 at 15:50