Heat the 1/2 cup of olive oil in a large soup pan on low-medium. When the oil is hot (3-5 minutes) add the chopped vegetables. Stir to coat the vegetables with oil. Cook the vegetables in the oil until they are soft. This will take about 30-40 minutes. Stir the mixture often.
While the vegetables are cooking, dissolve the bouillon cubes in hot water. You will need to add a total of 8 cups of water to the soup, but you can dissolve the bouillons in a portion of the total 8 cups. When the vegetables are cooked, add the water with the dissolved bouillons and additional water needed to make 8 cups total. Add the tomatoes and stir thoroughly.
Add the lentils, barley, fresh herbs and black pepper. Stir to mix thoroughly. Cover the pot and cook the soup on a low-medium heat for about 40 minutes. Test the barley to make sure it is cooked. Cooked barley should be firm, but you should be able to chew it.