Swipe typing can also take your system’s "Personal Dictionary" into account when suggesting words. To add words to your personal dictionary, make sure you enable the "Personal inking and typing dictionary" option from "Settings → Privacy & Security → Inking & typing personalization." Keep typing the word using the touch keyboard or physical keyboard in any app or field allowing text inputs. You can see if Windows added the word to the dictionary by going to "Personal dictionary" from the "Inking & typing personalization" section.