The window at the top left of the main screen contains the Bible text in the original language (Hebrew/Aramaic or Greek), equipped with a transliteration (a conversion to Roman script) and a word-for-word translation. By checking "Hebrew only" or "Greek only" in the toolbar above the window, the transliteration and interlinear translation are hidden and only the Hebrew or Greek text is shown.
Because the Old Testament is written in Hebrew (and a small portion in Aramaic) and the New Testament is written in Greek, the screen can look different ways.