When adding a suffix to a word, you usually do not have to change the spelling of that word. For example, you can ad the suffix ly to words such as love+ly= lovely, usual+ly= usually.When adding the suffix ness, or ly don't change the spelling of the word. Sometimes, there can be an exception. For example, eight+teen= eighteen. The extra t was dropped. When a word ends in y, change the y to an i before adding ly or ness. Example happy + ness= happiness. Do drop a silent e before adding a suffix that starts with a vowel. Example--cause+ing=causing. However, keep the silent e when adding a suffix beginning with a consanant. Example--hope+less=hopeless. Practice will allow you to get the hang of this.