They're not just vowel removal abbreviations or similar though, they seem like things that'd be common errors - 'missles' is how a lot of Americans pronounce 'missiles', if her film and television is any indication, for example. 'Careful' is one of those 'eh what can I say, English spelling is weird' words anyway - 'care', 'full', why shouldn't it be 'carefull'? I'm not a teacher, but I bet that's a common error.