Language is a “genetic” feature of a nation. A lot of things can be said about a nation by studying its language. Studying important works of different periods and identifying their form and semantic fields sheds light on our language and history. In this work, which has been written by taking this prime purpose into account, diachronic and simultaneous research about the expression of future tense in Turkish language has been conducted. In the study, qualitative research approach was adopted and scanning model was preferred.Consequently, it is revealed in this work that morphemes, whose primary function is future tense, have not been used only with this function since the first periods of Turkish language. These morphemes constitute a wide spectrum of meaning, including modality semantic fields such as request, certainty, intention, possibility, prediction and despair as well as their main function of expressing future tense. The main factors which create this wide spectrum of meaning are meaning feature of root and body of verbs with which morphemes are used, the type of the sentence, the type of the text and narration, and grammar units which determine the meaning such as adverbs, pronouns and adjectives which are used in sentences and in units above sentences.

Oghuz Turkish, future tense, modality, mood