haha ha pan ni bataa wo usuku nurimasu.

In a sentence like this, 母 usually means my mother.

Japanese often leaves out possessives like my when the relationship is obvious from context. So 母は... is commonly understood as As for my mother, ...

In an isolated textbook sentence, it can also feel a little general, like Mother ..., but in real usage it most often refers to the speaker’s own mother.

This is a very common question.

Japanese often uses:

• 母（はは） for my mother when talking to other people
• お母さん when talking to your mother, or when referring to someone else’s mother more politely

So:

• 母はパンにバターを薄くぬります。 = talking about my mother
• お母さんは... could sound like you are talking about someone else’s mother, or using a warmer/more conversational style

Textbooks sometimes simplify this, but the basic idea is:

• 母 = your own mother, in outward/reference style
• お母さん = respectful/familiar form

は marks the topic of the sentence.

So 母は means something like:

• As for my mother, ...

In English, we usually just translate it as the subject:

• My mother ...

But grammatically, は is not exactly the same as an English subject marker. It introduces what the sentence is about. Here, the sentence is talking about what the mother does.

With 塗る / ぬる (to spread/apply), the thing that receives the substance is often marked with に.

So in:

• パンにバターをぬる

the roles are:

• パンに = onto the bread / on the bread
• バターを = butter as the thing being spread

You can think of に here as marking the surface or target where something is applied.

Because バター is the direct object: it is the thing being spread.

So:

• パンに = onto the bread
• バターを = butter
• ぬります = spread/apply

A very useful pattern is:

A に B を ぬる
= spread/apply B on A

For example:

• 顔にクリームをぬる = apply cream to the face
• パンにジャムをぬる = spread jam on bread

Because 薄く is the adverb form of the い-adjective 薄い.

• 薄い = thin
• 薄く = thinly

To turn an い-adjective into an adverb, you usually change い to く.

So:

• 早い → 早く = quickly
• 遅い → 遅く = slowly/late
• 薄い → 薄く = thinly

Here 薄く modifies the verb ぬります, so it means spread thinly.

It modifies the verb ぬります.

So the meaning is:

• spread the butter thinly

It does not mean that the butter itself is inherently thin before being spread. It describes how the spreading is done.

So the structure is basically:

• バターを 薄く ぬります
• spread butter thinly

ぬります is the polite non-past form of the verb ぬる written in kanji as 塗る.

So:

• dictionary form: 塗る（ぬる）
• polite form: 塗ります（ぬります）

The non-past form in Japanese can refer to:

• a habitual action
• a general fact
• a future action, depending on context

So ぬります does not automatically mean only present tense in the English sense.

By itself, ぬります most naturally sounds like a habitual or general action.

So it often feels like:

• My mother spreads butter thinly on bread or
• My mother puts a thin layer of butter on bread

If you want to emphasize that it is happening right now, Japanese more often uses the -ている form:

• 母はパンにバターを薄くぬっています。

That sounds more like:

• My mother is spreading butter thinly on the bread.

Not completely.

Japanese word order is more flexible than English because particles show each word’s role. The verb, however, usually stays near the end.

So these are all possible:

• 母はパンにバターを薄くぬります。
• 母はバターをパンに薄くぬります。

The first one is very natural because パンにバターをぬる is a common pattern.

A good beginner rule is:

• keep the verb at the end
• keep modifiers like 薄く before the verb
• use particles to track the roles

Yes, but the nuance changes.

• 母はパンにバターを薄くぬります。
  = As for my mother, she spreads butter thinly on bread.
  This simply presents mother as the topic.

• 母がパンにバターを薄くぬります。
  = My mother is the one who spreads butter thinly on bread.
  This gives more focus to mother as the subject.

So は is more neutral/topic-setting, while が often sounds more focused or contrastive in this kind of sentence.

Yes, it can absolutely be written as 塗ります.

Textbooks often write some words in hiragana when:

• the kanji is less common for beginners
• they want to make reading easier

So both are fine:

• ぬります
• 塗ります

Likewise, the full sentence can be written as:

• 母はパンにバターを薄く塗ります。

Japanese usually does not mark singular vs. plural the way English does.

So パン could mean:

• bread in general
• a piece of bread
• slices of bread

In this sentence, English usually chooses bread or the bread depending on context, but the Japanese itself does not force one exact number.

This is very normal in Japanese: number is often left unstated unless it matters.

Here are the main readings:

• 母 = はは
• パン = pan
• バター = bataa
• 薄く = うすく
• ぬります / 塗ります = ぬります

One important point:
母 by itself in this sentence is read はは, not ぼ or かあ.

So the full sentence is read:

はは は パン に バター を うすく ぬります。