Informal vs Polite Japanese: How they differ in both simple and complex sentences

When speaking Japanese, it is always important to use the appropriate degree of politeness.

There are, broadly speaking, three levels of politeness. We can call these:

• Informal
• Polite
• “Super-polite”

The main difference between each of these comes down to verb forms. There are other differences too, but for the most part, you can vary the politeness of a sentence by simply changing the verb forms.

In this article, we’ll look at how to do that for both simple and complex sentences, as well as a few other things that differ at each level.

We’ll particularly focus on the informal and polite forms because:

1. the super-polite form is trickier, with a lot more nuance and specific expressions, and
2. in most situations where a higher degree of politeness is ideal, the regular polite form is usually good enough.

That said, we’ll still touch on the super-polite form to give you a more complete picture of Japanese politeness, but we’ll save the details of the super-polite form for another time.

Another challenge with politeness in Japanese is knowing when to use each form of language. You can find my dedicated article on that topic here.

Verb forms and different levels of politeness

Every verb in Japanese has a polite form and an informal form (also sometimes known as the “plain” or “dictionary” form).

Without getting into specifics, some verbs also have super-polite alternatives, while many others can instead be modified slightly to make them super-polite.

To put it in extremely simplified terms:

A sentence is generally as polite as the verb used at the end of the sentence.

In other words:

• If a sentence ends with a verb in the polite form, the whole sentence is polite.
• If a sentence ends with a verb in the informal form, the whole sentence is informal.

Here’s an example:

I will go to Tokyo tomorrow.

Quite simply, the use of “ikimasu”「行いきます」 or “iku”「行いく」 determines whether the sentence is polite or not. The rest of the sentence remains unchanged.

Here it is in our sentence structure diagram:

This sentence is in the present/future tense, but a number of other Japanese verb forms also have informal and polite alternatives, such as:

• the past tense (did)
• negative verb forms (does not do)
• the negative past tense (did not do)
• the potential form (can do)

In all cases, choosing the polite or informal form of the verb is the main factor that determines the politeness of a sentence.

Sentences ending in “desu”「です」

An important and very frequent “exception”, if we can call it that, is sentences that end in “desu”「です」.

My dedicated article about “desu”「です」 explains this in more detail, but essentially, “desu”「です」 itself is a polite-form verb, and its informal form is sometimes “da”「だ」, while at other times it is effectively nothing at all.

Let’s see an example of each.

I am a student.

Here, the polite form uses “desu”「です」, while the informal form replaces it with “da”「だ」. Pretty simple.

If a sentence ends with an i-adjective, however, the informal form instead drops the “desu”「です」 altogether, replacing it with nothing (though the “is” meaning is retained):

I am cold.

There are other permutations too, such as past tense and negative forms, that further complicate things and make “desu”「です」 one of the most misunderstood words for learners of Japanese. Check out my dedicated article about “desu”「です」 for a more detailed explanation and more examples.

Other differences

While verbs account for the main difference in politeness levels, particularly between informal and polite Japanese, there are a few words or particles that are generally more suited to one form over the others. We can’t possibly cover them all, but here are a few of the more notable ones.

“But”

The English word “but” can be expressed in a number of different ways in Japanese, and some of these are more informal than others. Here’s an example using two of the most common words for “but”:

I want to eat Japanese food at home, but I don’t know how to make it.

As shown here, “ga”「が」 is more polite, and “kedo”「けど」 is more informal. This is consistent with the verb forms used in this example.

That said, “kedo”「けど」 is often mixed into otherwise polite language, and there is absolutely nothing wrong with using “ga”「が」 with informal verbs, so there is quite a lot of flexibility here. It’s important to recognize, however, that certain expressions do have a polite or informal connotation to them.

“So / Because”

A similar example is the common words for saying “so” (or “because” if the parts of the English sentence are reversed), as in the following sentences:

It’s raining, so let’s take an umbrella. (Let’s take an umbrella because it’s raining.)

The words “kara”「から」 and “node”「ので」 both translate roughly as “so” when used like this, but “node”「ので」 is slightly more appropriate in polite or formal settings. However, like the “but” words, both can be used together with otherwise informal or polite language. There is similarly just a slightly stronger hint of politeness in “node”「ので」.

What can be confusing is that “node”「ので」 is typically used after a verb in the plain form despite it being considered more polite. Don’t let this fool you into thinking that informal verbs mid-sentence are always okay! This is quite an exception and is just due to the way “node”「ので」 attaches to the verb. We’ll touch on this again in the “Complex Sentences” section below.

Questions

One more example of expressions differing between informal and polite Japanese is the use of the question particle, “ka”「か」. Adding “ka”「か」 to the end of a sentence turns it into a question. This applies at all levels of politeness.

However, particularly in informal, spoken language, this “ka”「か」 is often dropped and intonation alone can be used to make something a question.

For example, this polite question:

Might be phrased simply as:

When spoken, “itta”「行いった」 is pronounced with a rising tone (note: this can vary by dialect) to make it a question rather than a statement. A similar effect can be achieved with polite language too, though it’s not quite as common.

Fortunately, we often do a very similar thing in English, so it’s usually not too hard to pick up on. Just say these two sentences to yourself and you’ll see what I mean:

Obviously, the grammatically “complete” way to ask the above question would be by starting with, “Did you go…”, but in certain cases, the above phrasing is used instead. The word order switch to make a question is kind of like the English version of the particle “ka”「か」, and in both cases, it’s possible to forgo this change and rely purely on intonation instead.

In any case, this is seen more commonly in informal Japanese, though not exclusively so.

Complex sentences and the use of polite/informal verb forms

Although verb forms are the main determinant of whether a sentence would be considered informal, polite or super-polite, not all verbs in a sentence need to take the same form.

For informal sentences, it’s quite simple – all the verbs will typically be in the informal/plain form.

Polite and super-polite sentences, however, will often contain a mixture of plain and polite verb forms.

That’s right – not only is it common, but it is grammatically correct to use plain form verbs within polite sentences in certain situations.

Identifying independent clauses

To get this right, we need to answer this important question about each verb:

Is it the main verb of an independent clause, or something else?

What does that mean, you ask?

An independent clause can be described as anything that forms a complete “thought”, and could therefore stand alone as a sentence by itself.

For example, consider this sentence:

I went to the park, but it was raining.

This has two independent clauses – “I went to the park”, and, “it was raining”. Each could, by themselves, be considered a complete sentence. They each form a complete thought independently of the other. The “but” stands in the middle to connect these two separate thoughts together.

Now consider this:

When I went to the park, it was raining.

Here, “when I went to the park”, is what’s called a dependent or subordinate clause. It is not a complete thought, and is instead qualifying or “setting up” the sentence for the main point being made. It needs something else in order for it to become a complete sentence.

(If you’re wondering, the key difference between “when” and “but” is that “when” modifies the rest of that clause and therefore becomes part of it, whereas “but” doesn’t modify anything – it just links the two clauses.)

While the grammatical structures in Japanese differ from those in English, the concept of the independent clause is the same.

Main verbs of independent clauses

Now that we know what independent clauses are, the main thing to remember is this:

In Japanese, for a full sentence to be polite (or super-polite), each independent clause should typically end with a verb in the polite (or super-polite) form.

Usually, where there are multiple independent clauses in a single sentence, they will be joined by a conjunction – a “joiner word”. Our above example in the polite form looks like this:

That is, we have two independent clauses, and these are joined by the particle “ga”「が」.

Importantly, so as to make this whole sentence polite, both verbs need to be in the polite form. In our sentence diagram, it looks like this:

If we only used the polite form for the last verb, and used the informal form “itta”「行いった」 instead of “ikimashita”「行いきました」, the sentence would not be particularly polite. It’s better than using informal forms for both verbs, but not by much.

This is why it’s important to recognize independent clauses.

Put simply, every independent clause should end with a verb in the appropriate form.

Verbs that are not the main verb of an independent clause

Now let’s look at an example of a verb that is not the main verb of an independent clause.

Japanese has many different expressions that include such verbs. A particularly common subset of these is noun phrases, which I will use to highlight this point, but the same applies to a wide range of other expressions in Japanese that form dependent clauses.

A noun phrase is a phrase, no matter how long it might be, that describes a single “thing”. In Japanese, noun phrases end with the “head noun”, and may or not have a description before them.

For example, the following are all noun phrases using the head noun, “sushi”.

Each of these refers to one “thing” – the sushi. The only difference is the level of detail used to describe it.

Noun phrases are also used to make up all kinds of adverbial and other useful expressions (many of which could be considered dependent clauses), such as:

If you want to learn more about noun phrases in Japanese, including how to form them, how to use them in sentences, and many useful expressions that apply them, check out my book, 80/20 Japanese.

Unlike independent clauses, verbs that make up part of a noun phrase are virtually always used in the plain/informal form, even in polite sentences. The same is true for verbs that appear in other kinds of dependent phrases and expressions (ie. where the verb is not the main verb of an independent clause)

Here’s an example of a polite sentence using one of the above noun phrases:

Here, “chichi ga katta sushi”「父ちちが買かったすし」 is a noun phrase, so the verb “katta”「買かった」 should be in the plain form. Even so, by ending the sentence with a polite form verb (tabemashita食たべました), the whole sentence would be considered polite.

If we put this into our sentence structure diagram, we can easily see which verb is the main verb of the sentence/clause, and which verb is not:

A silly way to help remember this distinction

One way to think about this is that each individual thought (ie. each independent clause) has one main verb, which is a kind of representative for that thought.

The representative must present themselves appropriately and consistently. They are either always informal, always polite, or always super-polite. They can choose to be more polite than necessary on occasion, but never less polite.

Meanwhile, many thoughts will also contain other verbs that are not the main verb. These verbs are not representatives, so the rules of politeness don’t apply to them. They are there purely for functional reasons – to serve a particular role – so they typically take the most functional form: the plain form. It is up to their representative (ie. the main verb of that clause) to ensure the appropriate degree of politeness is being used.

Other verb forms

There are several verb forms and endings that don’t have polite and informal alternatives, such as the teて-form, “~nagara”「～ながら」, “~tara”「～たら」, etc. The lack of informal/polite alternative forms should tell you everything – they are neither.

Usually, these kinds of verb-based expressions form dependent clauses, so they can be used as is, and the rest of the sentence will determine its politeness level.

There are some expressions that may be considered “too informal” for polite settings, or even “too stiff/polite” for informal settings. Some are also only suitable for spoken Japanese, while others are used exclusively in written Japanese.

Unfortunately, that needs to be learnt on a case-by-case basis. Rest assured, however, that most of the most common verb forms and expressions can be used in any setting, as long as the appropriate verb ending is used.

Key Takeaways

• Verb endings are the main things that differentiate informal, polite and super-polite sentences in Japanese
• A sentence is generally as polite as the verb used at the end of the sentence
• “Desu”「です」 is a polite-form verb whose informal form varies depending on context (read my article about “desu”「です」 for more detail)
• Some words and phrases are inherently more or less polite, although that doesn’t mean they can’t be used across different levels
• Generally, the main verb of each independent clause needs to have the right level of politeness
• Other verbs, such as those within noun phrases and dependent clauses, are primarily functional and can be expressed in the plain form, even in otherwise polite sentences.