I once had a chance to compare a couple of scripts a friend brought to a group meet-up, the kind of thing you only see if you know someone in the industry. The most immediate visual difference is chaos versus order. A regular commercial or narration script is usually this clean, timed document, maybe thirty seconds of polished corporate speak. The anime script was a mess of handwritten notes in the margins, timestamps scribbled out and rewritten, and these weird phonetic spellings next to lines.
It's not just about looks, though. The pacing is built differently. With regular voiceover, you're hitting specific beats to match a video edit that's already locked. In anime, the timing often has to lock to the animation, sure, but there's more room for the actor to stretch a reaction or a gasp because the animation is built to accommodate performance flourishes. The director might say 'hold that scream for two extra frames' right there on the page.
And the emotional notation is way more intense. Where a commercial script might say 'warm, friendly', an anime script will have these long, almost novel-like descriptions of a character's internal state mid-line. Something like 'Kazuki says this line not with anger, but with the crushing weight of remembering his failure to protect his sister, voice trembling on the edge of tears'. It's less instruction and more emotional blueprint.