A synthetic language, also called an inflected language, is a language which uses inflectional forms, such as affixes, as a primary means of indicating the grammatical function of the words in the language. An example of a synthetic language is Latin. The opposite of a synthetic language is an analytic language, also known as an isolating language, in which the word forms are mostly or totally fixed, and grammatical functions are indicated through the use of helper words and word order. Chinese is an example of an analytic language.

Synthetic languages can be further broken down into agglutinative and fusional categories.

For more information on synthetic languages, please see inflected language.