1. A processor-implemented method of building a custom word list for use in text operations on an electronic device, comprising the steps of: scanning a collection of text items associated with a user of the electronic device to identify words in the text items; assigning a weighting to each identified word; storing each identified word and its corresponding weighting; and determining a source of each text item in the collection of text items; wherein the step of assigning a weighting comprises the step of calculating the weighting for each identified word based on the source of the text item in which the word was identified; wherein the text item sources include a user text item source and an external text item source, wherein text items from the user text item source are assigned a higher weighting than text items from the external text item source.