There is nothing inherent about the characters in a script or the direction of writing that lends a particular writing system to representing language sounds by phonemes or by syllables or by anything else. Cherokee writing represents the Cherokee language by syllable but is based on the Roman alphabet which we think of as representing individual sounds. Different writing systems represent the speech sounds of language in different ways and to varying degrees of efficiency. Variant spellings in English seem to mark a difference in meaning in writing that might be signalled in other ways in oral communication. Script characters or letter symbols get turned into language.
Brain activity is very complex.
I am a 6th grade teacher in the Sacramento City Schools. Thanks for any input.