Her Personality:

Sayori is portrayed as the archetype of a Genki Girl, expressing a talkative and cheery disposition. She is very clumsy, noted for finding ways to accidentally hurt herself or to drop things. Regardless, she is shown to be a cunning individual who can trick others to get food. She is usually the only character, other than the protagonist, shown to break up arguments, Monika noting that her sentiments is necessary to keeping a relaxing atmosphere in the Literature Club (proven by her absence in Act 2). Monika notes that while she may look like a good leader, Sayori is usually better when it comes to dealing with people, notably at mediations. Sayori tries her best to help everyone be happy and dislikes attention directed at her well-being because she feels unworthy of anything that others have to offer her.

Sayori's depression makes her disorganized, and she often "cannot find a reason to get out of bed in the morning"; her room, which the protagonist regularly cleaned for her, is also noted to be untidy. The protagonist notes how there hasn't been much change in her, and the changes the protagonist notices in her later are due to Monika's interference, amplifying her depression and suicidal tendencies. Sayori also doesn't seem to think highly of herself. Her relationship with the protagonist and other people's happiness are her main coping mechanisms since she believes that if she makes everyone else happy, she will not have a reason whatsoever to be unhappy.

Try to think about what she might sound like in the Actual Game.

Ref: https://www.youtube.com/watch?v=5ZVRLvqDOLM