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
Three letter rule and "ka". Carney calls such words "exceptions which prove the rule, clearly marked as exotic by the spelling". Three letter rule In English spelling, the three letter rule (or short word rule) is the observation that one- and two-letter words tend to be function words such as "I", "at", "he", "if", "of", "or", etc. As a consequence of the rule, "content words" tend to have at least three letters. In particular, content words containing fewer than three phonemes may be augmented with letters which are phonetically redundant, such as "ebb, "add, "egg, "inn, "bee, "awe, "buy", "owe", etc. Many content