Well, when it comes to Arabic, the short vowels should be written out as accents of sorts. However, they are quite often missing in actual written text. However, even as a native Arabic speaker I will struggle with text written like that and it will take me a while to read it. That's because most Arabs(at least the Lebanese, Syrian and Egyptians I've mostly been exposed to) do not speak the written Arabic. Rather, we speak a colloquial language that will differ from one region to another. These are visibly descended from the formal, written, Arabic but they are not at all the same language. They have many different words, a completely different grammar, and very different pronunciation. So as far as most Arabs I know, the written Arabic is pretty much yet another foreign language they learn rather than their native language. The similarity between the written and spoken is similar to the difference between say Latin and languages that were descended from it(such as French).