Hi! So, as far as I know, when you have 'northern', 'southern',... you use it as an adjective, like: southern region, eastern people, western beer and so on. South, north, east and west are just the directions. I hope I helped :))

Hello!)) Here are some ex. when you can use these words. I wish you good luck. -people belong to ethnic groups and regional groups such as North African and Southern African. -World regions: North America, South America, Southern Africa, East Asia, North Africa, The Far East -You can use north, south, east and west as adjectives or adverbs and occasionally as nouns: More and more people are buying second homes on the south coast of Ireland. (adjective) After Bangkok, we drove north for about six hours without stopping. (adverb) Strong Atlantic winds are forecast in the west of Portugal. (noun) -You can use northern, southern, eastern and western to refer to larger areas or territory. We can only use them as adjectives: The northern parts of India have suffered severe flooding/Houses are more expensive in most western parts of the country.