Three letter rule poets such as John Milton alternated between short and long forms for function words, depending on whether they occurred on or off the meter. For instance: While many function words have more than two letters ("and", "she", "were", "therefore", etc.), the exceptions to the rule are rather two-letter content words. Only a few of these occur commonly in most texts: the words "go" (which also has a functional usage in the idiom "going to do something"), "ox" and, especially in American texts, "ax". English grammar is relatively flexible about converting words of one class to another, allowing verbal uses such
Word uses orthographic cues to delimit words such as switching between kanji (Chinese characters) and the two kana syllabaries. This is a fairly soft rule, because content words can also be written in hiragana for effect (though if done extensively spaces are typically added to maintain legibility). Vietnamese orthography, although using the Latin alphabet, delimits monosyllabic morphemes rather than words. In character encoding, word segmentation depends on which characters are defined as word dividers. Morphology is the study of word formation and structure. In synthetic languages, a single word stem (for example, "love") may have a number of different forms (for