Assumptive mood
The assumptive mood is an epistemic grammatical mood found in some languages, which indicates that the statement is assumed to be true, because it usually is under similar circumstances, although there may not be any specific evidence that it is true in this particular case. An English example, would be, "That must be my mother. " Another example in English, using a different modal verb, would be, "He should be a good worker. "
The assumptive mood can be found in the Wintu language, an extinct Native American language once spoken in California. An example of a Wintu sentence demonstrating this grammatical mood is: