Southmark's rhymes with:
birthmarks, pathmark's, benchmark's, benchmarks, birthmarks, bismarck's, caremark's, cellmark's, denmark's, deutschemark's, deutschemarks, earmarks, hallmark's, hallmarks, hartmarx, landmark's, landmarks, pathmark's, raymark's, trademarks, watermarks, westmark's
Southmark's sounds like:
southmark, stationers, steamers, steiner's, stonerock, sweeteners