Smyrna and Izmir are different names for the same city. Smyrna is what Izmir was called before it was taken by the Ottoman Turks.
Oriental, or Turkish, is a spice tobacco known for its nutty, somewhat "sweet and sour" flavor. It's a main component in English blends, along with Latakia (which is itself an Oriental that's been flavored with smoke).
This tobacco derives its name from the area in which it's grown: the Eastern Mediterranean. Each of the varietals, in fact, are named after the towns or regions they come from. Thus Yenidje
and Smyrna are Greek, Samsun and Izmir are Turkish, Drama is from Greece also, and Xanthe is from the region of Thrace, which is also in Greece. For all intents and purposes this is all one region, united for many years under Ottoman rule (hence the interchangeable terms "Oriental" and "Turkish".)
Oriental tobacco plants characteristically have a great deal of small leaves. The finished product ranges in color from yellow to brown, and is strongly aromatic. Its smell is reminiscent of used horse bedding, which could possibly explain why it's often mixed with Latakia.