* Old English: These are words that were part of the language before the Norman Conquest in 1066. They often have Germanic roots and tend to be shorter and more direct. Examples include "dog," "house," "friend," and "strong."
* Informal registers of English: These are words that are used in everyday speech, slang, or informal writing. They often have a playful, casual, or even irreverent tone. Examples include "chill," "awesome," "gonna," and "wanna."
* Words of foreign origin: Some words from other languages, particularly those from French or Latin, might have a more formal feel. However, there are also many words from other languages that have been adopted into English and are now considered informal, such as "dude" (from Spanish "dudo") or "okay" (from the Choctaw language).
* Newly coined words: These are words that have been created recently, often to describe new ideas, technologies, or trends. They can be informal or formal depending on their context. Examples include "selfie," "hashtag," and "clickbait."
It's important to note that the formality of a word is subjective and depends on the context in which it is used. A word that is considered informal in one situation might be perfectly acceptable in another. For example, "awesome" might be considered informal in a formal essay, but perfectly fine in a casual conversation.