Interjections. "Golly!" "Gee!" "Ouch!" "Wow!" An interjection is a spoken or written expression of emotion, often accompanied by an exclamation point.
Interestingly, but obviously outside the scope of this course, four letter curse words can be inserted here. Many four letter curse words are very versatile used not only as interjections but also as nouns verbs and other. A point of interest since learning a new language also means learning the no no words.