In a large pot add chicken broth and barley. Bring to a boil, reduce heat, cover and simmer for 15 minutes.
In the meantime, in a pan, add olive oil, garlic, carrots, celery, onions and sauté until vegetables are soft (~ 5 minutes).
Add sautéed vegetables to broth. Cook uncovered for 30 minutes.
Add sweet potatoes and season with pepper. Continue to cook uncovered for 20 minutes.
Stir in cooked turkey and cook 10 minutes longer.