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
Dual-route hypothesis to reading aloud processing, each of the two pathways consumes different amounts of limited attentional resources. The nonlexical pathway is thought to be more active and constructive as it assembles and selects the correct subword units from various potential combinations. For example, when reading the word "leaf", that adheres to spelling to sound rules, the reader must assemble and recognize the two-letter grapheme "ea" in order to produce the sound "ee" that corresponds to it. It engages in controlled processing and thus requires more attentional capacities, which can vary in amount depending on the complexity of the words being assembled. On the other