The main reason to edit an existing word list is that it makes typing faster. Words can be added manually to a word list to make sure that a certain word is present in the list. Deleting words (e.g. words that are spelled incorrectly) or editing their frequency are other possibilities to make certain words more important than others.

When word prediction is not going at a normal speed, cropping word lists can help. When the wordlist is getting too full (more than 50,000 words), word prediction may slow down. Skippy will indicate this as the program starts. Skippy then mentions the number of single words and word pairs in the word list and recommends that you crop the list. Cropping word lists can be essential to keep word prediction going smoothly. This way, all words with a low frequency can be deleted from the word list. This saves you the work of having to go through the list yourself to eliminate all unimportant words.