An example would be: "watashi wa cake o(お) tabetai". What does the お do? I tried on google translate and it seems it gives pertenence to that thing..like it belongs either to you or me..but I still need actual clarification.
There are three particles in Japanese which are typically spelled differently than they're pronounced:
Although you're hearing it correctly, in this case it is actually the particle を, marking a direct object:
This particle comes directly after the word or phrase it marks, like particles usually do in Japanese.
We have direct objects in English, too. But in English, we don't have a particle like を. Instead, we mark direct objects with word order:
Here, we can tell I is the subject, and the cake is the direct object. Why? Because of their location. If we switch them, the meaning changes completely:
Japanese word order is much more free than in English, because the Japanese language has little words like を and doesn't have to rely on word order all the time.