Interjections are words or phrases intended to convey the emotion of the author or speaker, such as, "My goodness," "Wow," or "Hmm." They can stand alone or be included as part of larger sentences.
Interjections are often found at the beginning of sentences, such as, "Oh yikes, this cake is terrible." In this example, the interjection is "Oh yikes." It is being used to convey the speaker's feeling of dismay. Although less common, they can also be used in the middle or at the end of sentences. "It is finally Friday, hooray!" and "I was going to go to the store, but darn it, I forgot," are examples of this.
Other times, an interjection may simply be a sound. "Huh" is commonly used to either express confusion or to seek agreement from a second party. Some other common sounds used as interjections are "Mmm," "Phew" and "Ugh." Sounds made to fill a verbal pause are also considered interjections.
Interjections are one of the eight major parts of speech, despite the fact that they are not necessary for comprehending the overall sentence. They can also be considered correct sentences when used alone. "Oh my gosh!" is considered a complete sentence, even though it lacks the usual subject and verb requirements.