Here's why it's considered a part of speech:
* It has a grammatical function: While interjections don't have a traditional grammatical relationship to other words in a sentence, they do convey information about the speaker's feelings or attitude.
* It often stands alone: They can be used independently, without being part of a complete sentence.
* It adds emphasis: Interjections add emotional impact and emphasis to sentences.
Examples of interjections:
* Wow! (Surprise)
* Ouch! (Pain)
* Hey! (Calling attention)
* Good grief! (Frustration)
* Oh dear! (Concern)