The Word Completion plugin can speed up your editing by suggesting completions of words as you type. To enable the plugin:

While editing, the Word Completion plugin will automatically display a pop-up list of words that begin with the letters you have already typed. Word suggestions are based upon words that appear elsewhere in your document and upon pre-defined keywords if your document is of a recognised format.

To insert a suggested word, double-click on it in the pop-up list or press AltNum, where Num is the number displayed next to your desired word.