Secondly, the use of individual words and sounds in combination to convey meaning is known as grammar (Bates et al, 1992). Word combinations are governed by grammar rules while conveying information. Syntax and morphology are both parts of grammar. The development of complex words and sentences is made possible by morphology, which focuses on the structure of the word itself. For instance, adding a "s" to the end of several words makes them plural (e.g., bird and birds). The smallest linguistic units with meaning are called morphemes. The smallest units of meaning in a language are called morphemes, which are composed of a string of one or more phonemes. While most morphemes are constructed from combinations of phonemes, some morphemes, notably one-letter words like "I" and "a," are also phonemes. Certain morphemes function as prefixes and suffixes on other words. For instance, the prefix "re-," found in words like "rewrite" and "repay," means "to do again," and the suffix "-est," found in words like "happiest" and "coolest," indicates "to the fullest." The study of words and other significant linguistic constructions like suffixes and prefixes is known as morphology. The relationship between words like "dog" and "dogs" or "walk" and "walking," as well as how individuals distinguish between those words, would be of interest to morphologists. Certain prefixes and suffixes, such as "un" or "ing" in the phrases "undo," "untie," or "doing," "tying," have their own meaning. Using a morphological rule in every situation causes young children to regularly make mistakes in this area (Bates et al., 1992). For instance, a young child might say, "I wented there" (past tense /ed/) or "I saw the deers" (plural /s/).