In Engpsh, the elements that make up a word are called morphemes. A morpheme is the smallest unit of meaning in a word. Some words are made up of one morpheme, such as "book" or "run." Other words are made up of multiple morphemes, such as "unhappy," which is made up of the prefix "un-" and the root word "happy."

There are two main types of morphemes: root morphemes and affixes. Root morphemes are the core of a word and carry its main meaning. Affixes are added to root morphemes to create new words or to change the meaning of a word. There are two types of affixes: prefixes and suffixes. Prefixes are added to the beginning of a word, and suffixes are added to the end of a word.

For example, the word "unhappy" is made up of the prefix "un-" and the root word "happy." The prefix "un-" changes the meaning of the word "happy" to its opposite, "unhappy." Similarly, the word "replay" is made up of the prefix "re-" and the root word "play." The prefix "re-" indicates that the action of "playing" is happening again.

I hope this helps! Let me know if you have any other questions.