Halcyon English is a dialect of American English, which came to be before the 22nd century. The differences between American English and Halcyon English are minute, typically just spelling changes in words, and contain very few pronounciation changes in words.
Differences Between The Dialects
In Halcyon English, the digraph ph has been replaced by the letter f. For example, the word telephone becomes telefone, pharmacy becomes farmacy, and trophy becomes trofy.
The digraph ck has been replaced by only the letter k. For example, the word kick becomes kik, hammock becomes hammok, and chicken becomes chiken.