maeba ha siroi desu.

In this sentence, は is the topic marker. It shows that 前歯 is the thing being talked about: as for the front teeth ...

When は is used as a particle, it is pronounced wa, not ha. This is one of the first irregular pronunciation rules learners meet in Japanese.

So:

• 前歯は = As for the front teeth...
• written with は
• pronounced まえば は -> actually まえば wa

This is different from は when it is part of a word, where it is normally pronounced ha.

白い is an い-adjective, meaning white.

In Japanese, many adjectives have their own full form, and white is not just 白 in this kind of sentence. The basic adjective is:

• 白い = white

The form 白 by itself is usually a noun-like stem or appears in compounds, not the normal predicate adjective form here.

So:

• 前歯は白い = The front teeth are white.

If you said just 白, it would not work as a normal adjective sentence here.

They can.

• 前歯は白い。 = plain/casual
• 前歯は白いです。 = polite

An い-adjective can already function as the predicate of the sentence, so 白い is complete by itself. Adding です makes the sentence more polite.

This often confuses English speakers because it looks like です means is, but that is not quite how Japanese works. In this sentence:

• 白い carries the descriptive meaning
• です mainly adds politeness

So 白いです does not mean that です is acting exactly like English is.

Yes, 白いです is standard modern Japanese.

Older or more formal grammar explanations sometimes say that です attaches naturally to nouns and な-adjectives, not to い-adjectives in the same way. That can make learners worry that 白いです is somehow wrong.

But in real modern Japanese, い-adjective + です is completely normal and common in polite speech.

Examples:

• 高いです = It is expensive/high.
• 寒いです = It is cold.
• 白いです = It is white.

So for a learner, you should treat 白いです as correct and useful.

Both can be possible in different contexts, but they do slightly different jobs.

• 前歯は白いです。 = As for the front teeth, they are white.
• 前歯が白いです。 = It is the front teeth that are white / The front teeth are white with more focus on the subject.

Very roughly:

• は marks the topic
• が marks the grammatical subject more directly and often sounds more specific, contrastive, or like new information

In a simple textbook sentence, は is very common because it introduces the thing being described.

If the context were something like Which teeth are white?, then が might sound more natural:

• 前歯が白いです。

If the topic is already the front teeth and you are just describing them, は is natural:

• 前歯は白いです。

It can mean either, depending on context.

Japanese nouns usually do not mark singular and plural as clearly as English nouns do. So 前歯 can mean:

• a front tooth
• front teeth

Context tells you which one is meant.

That is very normal in Japanese. The language often leaves number unspecified unless it matters.

Japanese often leaves out information that is obvious from context, especially with body parts.

So instead of saying:

• 私の前歯は白いです。 = My front teeth are white.

Japanese will often simply say:

• 前歯は白いです。

If the speaker is obviously talking about their own teeth, or the listener’s, or someone already being discussed, Japanese usually does not repeat the possessor.

This is very different from English, where we often feel we need my, your, his, etc.

Grammatically, yes, it is fine. But in real life, it may feel a bit context-dependent.

Why? Because saying The front teeth are white can sound like stating something obvious unless there is a contrast or special reason for saying it.

For example, it sounds more natural in contexts like:

• comparing front teeth with back teeth
• talking about tooth color after whitening
• describing a character or an animal
• commenting on uneven coloring

For example:

• 前歯は白いですが、奥歯は少し黄色いです。
  The front teeth are white, but the back teeth are a little yellow.

So the sentence is not wrong at all; it just may need context to sound fully natural.

The sentence is read:

• 前歯 = まえば (maeba)
• は = wa
• 白い = しろい (shiroi)
• です = desu

So the full reading is:

• まえば は しろい です
• naturally spoken: maeba wa shiroi desu

A small pronunciation note: です is often pronounced more like des in everyday speech, with the u very light or almost silent.

That’s right: normal Japanese writing usually does not use spaces.

So this sentence would normally be written as:

• 前歯は白いです。

Spaces are often added in beginner materials to help learners see the parts more clearly:

• 前歯 / は / 白い / です

This is only for learning convenience, not standard writing.

Yes. Just remove です:

• 前歯は白い。

That is the plain form.

So:

• 前歯は白いです。 = polite
• 前歯は白い。 = plain/casual

The core meaning stays the same; the difference is politeness and tone.

No, not in this case.

The normal order here is:

• topic + は + adjective + です

So:

• 前歯は白いです。

Japanese word order is more flexible than English in some situations, but particles like は help organize the sentence, and you cannot freely scramble everything.

前歯です白い is not grammatical.

For a beginner, it is safest to remember this pattern:

• A は B です for noun sentences
• A は い-adjective です for polite adjective sentences

So this sentence fits the second pattern:

• 前歯は白いです。