They are, as far as I have seen, mostly typos and sentences which have an awkward structure. For example, when a player commits suicide, it is written "comitted" instead of "committed". Another example that comes to mind is the structure of the sentence which gives players a tip on timing airstrikes (I haven't got the exact sentence in mind, but it basically tells you to time your airstrikes because they take a few seconds before hitting their target).
I would like to help correct all these little things and just to do my (very little) part in helping this great game grow. I could compile the corrected text either in an MS Word file or in a private message. It isn't much and perhaps you've already fixed all of these things in Beta 4, but if you haven't, I'm offering to help.