You are misreading the Bible
10 Sing unto the LORD a new song, and his praise from the end of the earth, ye that go down to the sea, and all that is therein; the isles, and the inhabitants thereof.11 Let the wilderness and the cities thereof lift up their voice, the villages that Kedar doth inhabit: let the inhabitants of the rock sing, let them shout from the top of the mountains.
12 Let them give glory unto the LORD, and declare his praise in the islands.
Isaiah is mentioning several places, not just Kedar. He mentions the coastlines and the islands. The "inhabitants of the rock" in verse 11 is thought to refer to Sela (Edom).
Isaiah is essentially saying "from the sea to the desert." You just pick out the desert.
Let them give glory unto the Lord, and declare His praise in the inlands.
Very clever of you to change "islands" to "inlands."