She sounds to me like both my DD(who is 5 in a month) and DS1 (who is 3y 7mths and funnily enough a leo too!). DD will wail like you've described, and so will DS1 though for different reasons. DD will cry if she can't see things or people are in her way. DS1 will wail when he can't do stuff and then won't tell me what's wrong. They could both talk underwater with a mouth full of marbles, so it's not a language issue for us either.

The only thing you have said (or maybe alluded to) which I might be concerned about would be her anxiety about things. The rest of it sounds like she is just being a challenging 4yo. DS1 is really, I mean REALLY pushing my buttons with his behaviour lately (hitting, ignoring instrucions/rules, doing what he know's he shouldn't...) and DD has attitude plus (talking back, being rude, being entitled, threats to DS1 and her friends, being a bully to younger kids), so for me between them, I am going insane.