In writing system each character generally represents a word. That typically means that the system requires lots of characters and is difficult to learn. In contrast, in a$($n$)$ writing system, each character represents a sequence of sounds, usually a combination of a consonant plus a vowel. These systems generally require fewer characters, so they are easier to learn, but they are best suited for representing languages that have fairly simple sound combinations. In writing systems, each character represents an individual sound. Such systems require the fewest characters and are generally considered the most efficient for purposes of learning and representing the language. Among this last type of writing, there are subtypes. In one subtype, the writing system consists only of characters that represent consonant sounds, and vowels are not represented overtly in the writing. This is called a$($n Another subtype represents the consonants as the main characters with different vowels indicated by diacritic marks above or below the consonant. This system is called $a(n)$