Learn Hardcore Esperanto: Mi estas libera.

In Esperanto, estas is the present tense form of the verb esti (to be). Whenever you want to say I am, you are, he/she/it is, and so on, you use estas for all subjects. There’s no separate form like in English (am/are/is).

What part of speech is libera here?

The word libera is an adjective meaning free (as in unrestrained or unoccupied). In Esperanto, adjectives typically end in -a, and libera describes the state or condition of the subject (Mi).

Does the sentence change if the speaker is female or male?

No, it doesn’t. Esperanto adjectives and verbs do not change based on the speaker’s gender. The sentence Mi estas libera is valid for anyone regardless of their gender.

Is it necessary to say Mi at the beginning, or can I just say estas libera?

In everyday Esperanto, people usually keep the pronoun Mi to avoid confusion, particularly in longer conversations. However, in casual speech, if the context is clear, you might sometimes hear just Estas libera. Still, it’s more standard and clear to include Mi.