Volitive modality

Volitive modality is a linguistic modality that indicates the desires, wishes or fears of the speaker. It is classified as a subcategory of deontic modality.

Realisation in speech

Volitive moods are a category of grammatical moods that are used to express volitive modality. Examples are the optative, desiderative and imprecative moods.
However, many languages have other ways to express volitive modality, for example modal verbs.

Esperanto

has a volitive verb form that is formed by adding a -u to the verb stem and used to indicate that an action or state is desired, requested, ordered, or aimed for.
The verb form is formally called volitive, but in practice, it can be seen as a broader deontic form, rather than a pure volitive form, since it is also used to express orders and commands besides wishes and desires.
Examples:

Venu. ― "Come."
Donu ĝin al mi. ― "Give it to me."
Ni faru tion. ― "Let's do that."
Mi iru dormi. ― "I ought to go to sleep."
Via infano sukcesu en la vivo. ― "May your child be successful in life."
Mi volas, ke vi helpu min. ― "I want you to help me."
Ŝi petas, ke mi silentu. ― "She asks that I be silent."