Mi restos hejme hodiaŭ, ĉar mi ankoraŭ estas laca.

Not usually. The verb resti most often means to remain or to stay.

So Mi restos hejme means I will stay home. If you want rest in the sense of relaxing, Esperanto more often uses ripozi.

-os is the Esperanto future-tense ending.

So:

• restas = stays / is staying
• restis = stayed
• restos = will stay

That is why mi restos means I will stay.

Hejmo is the noun home.
Hejme is the adverb meaning at home.

Esperanto often uses the -e ending to make an adverbial form. With hejmo, the common set is:

• hejmo = home
• hejme = at home
• hejmen = homeward / to home

So Mi restos hejme means I will stay at home.

Because hejme already includes that meaning. It does the job of at home by itself.

An English speaker may expect something like ĉe hejmo or en hejmo, but hejme is the normal idiomatic form. You can say more literal phrases like en la hejmo, but that sounds more like in the home than the everyday idea at home.

Hodiaŭ means today. It is an adverb of time.

Its position is fairly flexible. For example, these are all possible:

• Mi restos hejme hodiaŭ
• Hodiaŭ mi restos hejme
• Mi hodiaŭ restos hejme

The version in the sentence is completely natural. Moving hodiaŭ mainly changes emphasis, not the basic meaning.

Ĉar means because. It introduces the reason:

• Mi restos hejme hodiaŭ = main idea
• ĉar mi ankoraŭ estas laca = reason

Unlike some languages, Esperanto does not force a special word order after ĉar. The clause keeps normal order:

• mi = subject
• estas = verb
• laca = adjective complement

So ĉar mi ankoraŭ estas laca is structurally very straightforward.

Because the second clause has its own subject, and Esperanto normally states it clearly.

In English, you also say because I am still tired, not just because am still tired. The same logic applies here: mi is needed in the subordinate clause.

Here ankoraŭ means still.

So mi ankoraŭ estas laca means I am still tired. In other contexts, ankoraŭ can sometimes be translated as yet, depending on the sentence.

That is the most natural position here. It modifies the idea of still being tired.

Esperanto adverbs are fairly flexible, but mi ankoraŭ estas laca is the most neutral way to say it. Putting ankoraŭ elsewhere is sometimes possible, but this version is the clearest and most standard for a learner.

Because laca is not a direct object here. It is a predicate adjective after estas.

In mi estas laca, laca describes mi. It does not receive the action of the verb, so it does not take -n.

Compare:

• Mi vidas la hundon = direct object, so hundon
• Mi estas laca = description of the subject, so just laca

No. Esperanto adjectives do not change for masculine or feminine, because Esperanto does not have grammatical gender in that way.

So laca can describe a man, a woman, or anyone else. The form only changes for things like plural:

• Mi estas laca = I am tired
• Ili estas lacaj = They are tired

It is standard and very common to put a comma before ĉar when it introduces a subordinate clause.

The comma helps separate the main statement from the reason:

• Mi restos hejme hodiaŭ, ĉar mi ankoraŭ estas laca.

You may occasionally see punctuation handled a bit more loosely, but this comma is the normal choice in careful writing.

Ĉ is pronounced like ch in church. So ĉar sounds roughly like char.

Ŭ is a very short glide, somewhat like a brief w sound. In hodiaŭ and ankoraŭ, it helps form the ending aŭ, which sounds roughly like the ow in how.

So very approximately:

• ĉar ≈ char
• hodiaŭ ≈ ho-di-ow
• ankoraŭ ≈ an-ko-row