I recently went to a OO website and read this:
In the English language, two letters have caused the most tragic breach in all of Christendom. In the Aramaic langauge, the difference is in one letter, Dolath vs. Beth--the difference between the two is a small line on the bottom and dot in the center. These prepositions while short and subtle, contain within their meanings the difference between truth and fiction. In as far as these refer to the language of Chalcedon, the Oriental Orthodox follow the traditional terminology using the preposition "of," whereas the Byzantine Orthodox use the preposition "in."
The question then comes in how these terms are used in regards to Christology. In the Nicene-Contantinopolian Creed, we see that "Christ was conceived of the Holy Spirit and of the Virgin Mary," thus the foundation is made clear. In terms of Christology the Oriental understanding is that Christ is "One Nature--the Logos Incarnate," of the full humanity and full divinity. The Byzantine understanding is that Christ is in two natures, full humanity and full divinity.
Just as all of us are of our mother and father and not in our mother and father, so too is the nature of Christ. If Christ is in full humanity and in full divinity, then He is separate in two persons as the Nestorians teach. Imagine your nature in your mother and your father; you are then two different people. If however your nature is of your mother and your father, then you are one person.
This is the linguistic difference which separated the Orientals from the Byzantines.
It really helped me better understand the difference between "of" and "in". I always understood there existed linguistic differences between the OO and EO, but this little essay helped me better grasp the situation. I know its just baby steps for those of you better educated in this area, but at least its a few little steps in the right direction!