Writing dialogue is very different to writing prose. In scripts, characters talk in sentence fragments which may not look grammatically correct on the printed page, but they sound convincing because that is the way we converse. Scriptwriting also has to portray a set situation and create a persona for the reader/performer of the text, even in the case of narration. Is this spoken by someone young or old? Are they male or female? Should the words be delivered in a soothing, cheerful or businesslike manner? Fundamentally, is this script convincing?