In a large kettle or Dutch oven, combine water, barley, and bouillon cubes. Bring to boiling; reduce heat. Cover and simmer for 10 minutes.
Meanwhile, in a 12-inch skillet, cook mushrooms, onions, carrots, and celery in oil until tender but not brown.
Add vegetables, parsley, tamari sauce or soy sauce, dillweed, salt, and pepper to barley mixture. Cook, uncovered, for 10 to 15 minutes or until hot. Makes 6 to 8 servings.