Standard word lists that are often used for such operations as predictive text, spell checking, and word completion are based on general linguistic data that might not accurately reflect actual text usage patterns of particular users. Systems and methods of building and using a custom word list for use in text operations on an electronic device are provided. A collection of text items associated with a user of the electronic device is scanned to identify words in the text items. A weighting is then assigned to each identified word, and the words and corresponding weightings are stored.