Here's why:
* Emotional Expression: Interjections are used to express strong emotions or reactions, which are more readily conveyed through spoken language and casual writing.
* Informal Tone: They often contribute to a more conversational and informal tone, making them less common in formal written pieces like academic essays or official documents.
* Suddenness: Interjections are often used to express sudden reactions or exclamations, which are more typical in spontaneous speech.
However, interjections can occasionally appear in formal writing, but they are usually used sparingly and strategically to emphasize a particular emotion or reaction.
Examples:
* Informal writing: "Ouch! That really hurt!"
* Spoken language: "Wow, that was amazing!"
* Formal writing: "Alas, the experiment failed." (Used for dramatic effect)
In conclusion, while interjections are prevalent in informal communication, they can be used in formal writing to add emotional impact or to express sudden reactions.