La hipoteko kaj la imposto estas grandaj elspezoj.

In Esperanto, verbs do not change for singular or plural subjects.

So:

• estas = is / are
• estis = was / were
• estos = will be

That means estas works for both:

• La hipoteko estas granda. = The mortgage is large.
• La hipoteko kaj la imposto estas grandaj. = The mortgage and the tax are large.

Unlike English, Esperanto does not have separate forms like is and are.

The ending -j marks the plural in Esperanto.

Here, the subject names two things, so the complement is plural too:

• elspezo = expense
• elspezoj = expenses

And adjectives must agree with the noun they describe:

• granda elspezo = a large expense
• grandaj elspezoj = large expenses

So:

• elspezoj is plural because there is more than one expense
• grandaj is plural because it describes elspezoj

This agreement is a very regular feature of Esperanto.

Because the sentence is talking about two separate expenses: the mortgage and the tax.

So the idea is:

• one expense → granda elspezo
• more than one expense → grandaj elspezoj

If you said granda elspezo, that would sound singular, as if both things together were being treated as one single expense. In this sentence, Esperanto normally uses the plural: grandaj elspezoj.

These are basic Esperanto word-class endings:

• -o = noun
• -a = adjective

So in this sentence:

• hipotek-o = mortgage
• impost-o = tax
• elspez-o = expense
• grand-a = large

Then the plural -j gets added where needed:

• elspezoj = expenses
• grandaj = large, plural

This regular ending system is one of the main building blocks of Esperanto.

Because there is no direct object in this sentence.

The verb esti means to be, and it links the subject to a description or identification. It does not take a direct object.

So here:

• La hipoteko kaj la imposto = the subject
• estas = are
• grandaj elspezoj = what the subject is described as

Since grandaj elspezoj is not a direct object, it does not get -n.

Compare:

• Mi vidas la domon. = I see the house.
  Here domon gets -n because it is a direct object.
• La domo estas granda. = The house is big.
  No -n, because granda is just a description.

Because the sentence refers to two specific things: the mortgage and the tax.

Repeating la before each noun is very natural and very clear in Esperanto:

• la hipoteko kaj la imposto

This clearly marks both nouns as definite.

Sometimes in coordinated phrases, Esperanto can omit a repeated article if the meaning is still clear, but using la with each noun is the safest and most standard way to express the mortgage and the tax as two definite items.

Kaj means and.

It joins two equal parts:

• la hipoteko
• la imposto

So:

• La hipoteko kaj la imposto = The mortgage and the tax

It works very much like English and.

Yes, it can go after, but putting it before the noun is the most neutral and common order.

So:

• grandaj elspezoj = normal, neutral
• elspezoj grandaj = possible, but less neutral and often more stylistic or emphatic

For learners, it is best to treat adjective + noun as the default pattern.

Yes. It is related to the idea of spending.

• elspezi = to spend
• elspezo = an expense
• elspezoj = expenses

This is very common in Esperanto: a root can be turned into different kinds of words by changing the ending.

For example:

• verb: elspezi
• noun: elspezo
• adjective: elspeza if needed in context

This makes vocabulary more systematic than in English.

The given order is the most straightforward and natural:

• La hipoteko kaj la imposto estas grandaj elspezoj.

Esperanto word order is fairly flexible, because endings carry a lot of grammatical information. But not every possible order sounds equally natural.

For ordinary statements, this pattern is best:

• subject → verb → complement

So this sentence is a good model to follow.