Because there was no printing press back then, scribes copied documents by hand. Manuscript copying is a difficult task. Scribes made little alterations to manuscripts as they copied them—a word here, a phrase there. The more often something was changed, the more likely it was that someone would notice this and complain. Complaints could be about anything from the style of handwriting to the color of ink used. When many complaints were made against one scribe, his employer would hire another one. The most common complaint against scribes was spelling error. This is not surprising since spell-checking computers today can't compare notes with other computers; they have to rely on human input. So if someone makes a mistake typing "computer" instead of "cogitation," for example, it'll never be detected. Spell-checkers only work for words that people know how to spell. Also, computers don't understand context or meaning when checking spelling, so if you're using abbreviations or slang, you're going to make mistakes. For these reasons, spelling errors remain among the most common complaints against scribes today. Another common complaint was lack of clarity in writing. If someone wanted to criticize someone's writing skill, they would say that he or she used unclear language. Clarity in writing requires explaining everything clearly up front so that there are no questions about what is being said.