Why couldn't grace wexler read sydelle's hand notes?

if you read the book you would understand that Grace Wexler toke the notes with her parent Mr. Hoo she took them to solve out the mystery because mr.ed plum read Sam westing will which would help in the game and only one person had those notes SyDELLe and she wrote them in polish because she did not trust them for she knew they would steal it i no what you think SyDELLe murdered him well let me tell you a hint one is a big lire and one is a good actor some doctors just have it in them but i have to go so here is a part of a song i sing America thy beautiful

- rkh