watasi ha wakaranai tango wo nando mo zisyoapuri de sirabemasu.

Because Japanese puts modifiers before the noun they describe.

So 分からない単語 literally means words that I don’t understand or unfamiliar words.

This is called a relative clause. Japanese does not need a word like that, which, or who here.

• 分からない単語 = words I don’t understand
• literally: not-understand words

English says the words that I don’t understand, but Japanese just puts the whole descriptive part before 単語.

Both can work, but the nuance is a little different.

• 分からない単語 = words whose meaning I don’t understand
• 知らない単語 = words I don’t know / words I’m unfamiliar with

In this sentence, 分からない suggests that when the speaker sees the word, they do not understand it, so they look it up.

For vocabulary, both are common, but:

• 知らない単語 often focuses on the word being unknown to you
• 分からない単語 often focuses on not understanding the meaning

は marks the topic of the sentence.

So 私は means something like:

• as for me
• I
• speaking of me

It does not work exactly like an English subject marker, but in many simple sentences it is translated as I.

Also, in natural Japanese, 私 is often omitted if it is already clear who is speaking. So a Japanese speaker might simply say:

分からない単語を何度も辞書アプリで調べます。

を marks the direct object of the verb.

Here, the verb is 調べます meaning look up / investigate / check, and the thing being looked up is 分からない単語.

So:

• 分からない単語を調べます = I look up words I don’t understand

A simple pattern is:

• X を 調べる = to look up / check / investigate X

何度も means many times, repeatedly, or over and over.

Breakdown:

• 何度 = how many times / how often / number of times
• も adds the sense of even, as many as, or repeatedly, depending on context

In this sentence, 何度も means the speaker looks up those words repeatedly.

So:

• 何度も調べます = look up again and again / many times

Here, で marks the means, tool, or method used to do something.

So:

• 辞書アプリで調べます = look it up with / using a dictionary app

Common uses of で include:

• place where an action happens
• tool or method used for an action

In this sentence, it is the tool/method use:

• 箸で食べます = eat with chopsticks
• スマホで調べます = look it up with a smartphone
• 辞書アプリで調べます = look it up with a dictionary app

Because Japanese verbs usually come at the end.

A basic Japanese sentence pattern is often:

• topic + object + other information + verb

So this sentence follows a normal Japanese order:

• 私は
• 分からない単語を
• 何度も
• 辞書アプリで
• 調べます

English often puts the verb earlier, but Japanese usually saves it for the end.

It is the polite non-past form.

That means it can mean:

• present habitual: I look up
• future: I will look up

In this sentence, the most natural interpretation is habitual:

• I look up words I don’t understand many times using a dictionary app

Japanese often relies on context to show whether something is present or future.

調べる is a very common general verb meaning to check, to look up, or to investigate.

For looking up words, 辞書で調べる is completely natural.

You may also learn 辞書を引く, which literally means to consult a dictionary. That is also correct, especially for traditional dictionary use.

Difference in feel:

• 調べる = broad, general, very common
• 辞書を引く = specifically consult a dictionary

With 辞書アプリ, 調べる sounds especially natural.

No. Normal Japanese writing usually does not use spaces between words.

So this sentence would normally be written as:

私は分からない単語を何度も辞書アプリで調べます。

Learner materials often add spaces to make the structure easier to see.

Yes, to some extent. Japanese word order is more flexible than English, as long as the particles make the roles clear.

For example, these are still understandable:

• 私は辞書アプリで分からない単語を何度も調べます。
• 分からない単語を私は何度も辞書アプリで調べます。

But the most neutral and natural order is usually the one you were given.

The important thing is that the particles show the grammatical role:

• は = topic
• を = object
• で = means/tool

Yes, very often.

Japanese frequently leaves out subjects and topics when they are already obvious from context.

So instead of:

私は分からない単語を何度も辞書アプリで調べます。

a speaker might simply say:

分からない単語を何度も辞書アプリで調べます。

That would still naturally mean I look up words I don’t understand many times using a dictionary app, if the speaker is talking about their own habits.