What does Pendle Hill in Lancashire have to do with East Timor and the Gobi Desert and Bredon Hill in Worcestershire?
Though Pendle Hill is teeming with witches, this is not a supernatural question. Pendle used to be called Penhul, from Pen in the Cumbric language meaning hill, and hul in Old English meaning hill. Once we moderns had added the Hill onto Pendle, we got Pendle Hill, or Hill-Hill Hill.
Timor comes from timur in Malay, and guess what timur means? You're damned right, dear reader, it means East, because Timor lies at the Eastern end of a chain of islands. So East Timor is East East.
The Mongolian for desert is Gobi, thus the Desert Desert; and the same thing applies to the Sahara Desert (from Arabic çaḥrā, meaning exactly what you guessed).
And so on and so forth round and round this sad and repetitious globe. People, of course, name things for what they are. Then new people arrive, don't understand the name and think that they are clarifying things, when in fact they are building an unnecessary yet delightful heap of verbiage.
Yet I only know of two places that have achieved the hat trick: Pendle Hill and Bredon Hill in Worcestershire, which comes from Bre (Celtic) Don (Old English) Hill, and therefore also means Hill Hill Hill.
Which leads me to a not-that-good A.E. Housman poem:
In summertime on Bredon
The bells they sound so clear;
Round both the shires they ring them
In steeples far and near,
A happy noise to hear.
The remainder, if you want it, is here.
To be fair, you can see why they called it a desert.