If in doubt about ie or ei, when the seem of your vowel is as in brief /i:/, we spell it ie; but following the letter c, we spell it ei: … So with that said, DSL occupies the center-ground for pace. You may check out the table previously mentioned https://spelling-mistake-kaise-su26047.webbuzzfeed.com/28512591/not-known-details-about-spelling-mistake