Researchers discovered, however, that the ability to read single Serbo-Croatian words, which are written to represent units of sound, like the Greek, is unaffected by how often they occur, whether they are new to the reader or on the context. This suggests that scripts without vowels must be read lexically while scripts with vowels can be read phonologically-at least when they are presented as single words. Baluch's research on Farsi argues not. Iranians read their unvocalised words lexically, just like readers of Hebrew. But they read words whose spelling represents units of sound phonologically like Serbo-Croatian.
Vowels are powerful.
In all languages, readers find it easier to learn to pronounce words that they have never read before if the words contain vowels than if they do not. Becoming literate, for example, using the Greek alphabet would be on the whole easier than with the Phoenician. Greeks would have had more difficulty than Phoenicians as they began reading words. They would have to learn the rules for pronouncing written words. But once they acquired this ability they could outread most Phoenicians.