Characterizer (formerly Kanjilish) is an add-on for the Firefox browser. The add-on changes the first character of an English word to a kanji character with a similar basic meaning to that word. For example, the word "example" would be replaced by "例xample." Whole words can optionally also be replaced.
Users can select from, create, and modify various word replacement "profiles", which alter the words that trigger a replacement character's appearance.