24. A processor-implemented system for building a custom word list for use in text operations on an electronic device, comprising: a first data store for storing a collection of text items associated with a user of the electronic device; a scanning module configured to scan the collection of text items to identify words in the text items; a weighting module configured to assign a weighting to each identified word; a second data store for storing each identified word and its corresponding weighting; and a module configured to determine a source of each text item in the collection of text items; wherein the weighting module calculates 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.
24. A processor-implemented system for building a custom word list for use in text operations on an electronic device, comprising: a first data store for storing a collection of text items associated with a user of the electronic device; a scanning module configured to scan the collection of text items to identify words in the text items; a weighting module configured to assign a weighting to each identified word; a second data store for storing each identified word and its corresponding weighting; and a module configured to determine a source of each text item in the collection of text items; wherein the weighting module calculates 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. 28. The system of claim 24 , wherein the first data store, the scanning module, the weighting module, and the second data store are implemented at a computer system, further comprising a word list loader at the electronic device configured to receive the identified words and their corresponding weightings from the second data store, and to store the identified words and their corresponding weightings at the electronic device.