La luanto bezonas almenaŭ du ŝlosilojn.

Because it is:

• plural: -j
• accusative (direct object): -n

So:

• ŝlosilo = a key
• ŝlosiloj = keys
• ŝlosilojn = keys, when they are the direct object of the verb

In this sentence, the tenant needs the keys, so keys is the direct object. Esperanto marks that with -n.

Yes. In Esperanto, after numbers like du, tri, kvar, and so on, the noun is normally plural.

So you say:

• du ŝlosiloj = two keys
• tri libroj = three books

Then if that whole noun phrase is the direct object, you add -n as well:

• Mi havas du ŝlosilojn. = I have two keys.

So in your sentence, du ŝlosilojn is exactly what you would expect.

La is the definite article, meaning the.

So:

• luanto = a tenant / tenant
• la luanto = the tenant

Esperanto has only one article, la. It does not change for gender, number, or case. Even when the noun gets plural or accusative endings, la stays the same.

Examples:

• la luanto = the tenant
• la luantoj = the tenants
• la luanton = the tenant (as direct object)

Luanto comes from the verb lui, which means to rent.

The ending -ant- is an active participle meaning something like someone who is doing the action, and -o makes it a noun.

So:

• lui = to rent
• luanto = a person who rents

In normal usage, luanto means tenant.

A helpful contrast is:

• luanto = tenant, renter
• luiganto = landlord / lessor, the person who rents something out

So luanto is the person receiving the rented place or item.

In Esperanto, -as marks the present tense.

So:

• bezoni = to need
• bezonas = needs / need / am needing / is needing, depending on context

Esperanto verb endings do not change with the subject:

• mi bezonas = I need
• vi bezonas = you need
• la luanto bezonas = the tenant needs

That makes verb conjugation much simpler than in English.

Almenaŭ means at least.

It tells you the minimum number needed. So almenaŭ du ŝlosilojn means at least two keys.

You can use almenaŭ with numbers, amounts, or even more general ideas:

• almenaŭ tri homoj = at least three people
• atendu almenaŭ horon = wait at least an hour

In your sentence, it modifies du ŝlosilojn.

Because numbers in Esperanto usually do not change form.

So:

• du = two
• kun du amikoj = with two friends
• mi vidas du amikojn = I see two friends

The noun changes when needed, but the number itself stays the same.

That is why you get du ŝlosilojn, not a changed form of du.

A rough pronunciation guide is:

shlo-see-LOYN

More exactly:

• ŝ sounds like English sh
• o is a pure o sound
• si here sounds like see
• loj sounds roughly like loy
• -n is clearly pronounced at the end

Esperanto stress is always on the second-to-last syllable, so the stress is on lo:

ŝlo-si-LOJN

Also:

• ŝlosilo = shlo-SEE-lo
• ŝlosilojn = shlo-si-LOJN

Yes, to some extent. Because Esperanto marks the direct object with -n, word order is more flexible than in English.

The neutral order is:

• La luanto bezonas almenaŭ du ŝlosilojn.

But you could also say:

• Almenaŭ du ŝlosilojn bezonas la luanto.

That would sound more emphatic, focusing on at least two keys.

Even so, beginners should usually stick with the standard subject–verb–object order unless they have a reason to emphasize something.

Yes, ŝlosilo is the normal Esperanto word for a physical key.

It comes from ŝlosi, meaning to lock.

So:

• ŝlosi = to lock
• ŝlosilo = key

Like many Esperanto words, it is built very regularly. Once you know the root ŝlos-, related words become easier to recognize.

Grammatically, you can sometimes omit la, but the meaning changes.

• La luanto = the tenant
• luanto = a tenant / tenant

So:

• La luanto bezonas almenaŭ du ŝlosilojn. = The tenant needs at least two keys.
• Luanto bezonas almenaŭ du ŝlosilojn. = A tenant needs at least two keys, or tenant needs at least two keys in a more general sense

If the sentence is about one specific tenant, la is the natural choice.