sensei ga okutte kureta rinku kara, nihongo no kizi wo yonda.

Here, 先生が送ってくれた is a clause modifying リンク.

So 先生 is the subject of the verb 送ってくれた, and が marks that subject:

• 先生が送ってくれたリンク
• the link that the teacher sent

In relative clauses like this, が is often the most natural choice.

Could は appear? Sometimes, in a different context, yes, but が is the normal choice when you are simply identifying who performed the action inside the clause.

送ってくれた is 送る plus くれる.

• 送る = to send
• 〜てくれる = to do something for me / for us or for someone close to the speaker

So 送ってくれた does not just mean that the teacher sent the link. It adds the nuance that the teacher sent it to the speaker, as a beneficial action.

Compare:

• 先生が送ったリンク = the link that the teacher sent
• 先生が送ってくれたリンク = the link that the teacher sent to me / for me

That くれた nuance is very common and important in Japanese.

Because くれる already strongly suggests that the action was done for the speaker.

So in this sentence, the idea of the teacher sent me the link is built into 送ってくれた, and Japanese does not need to say 私に unless there is a special reason to emphasize it.

For example:

• 先生が私にリンクを送ってくれた = explicitly says to me
• 先生が送ってくれたリンク = still naturally understood as the link the teacher sent me

Japanese often leaves out things that are clear from context.

This is a noun-modifying clause.

Japanese puts the descriptive clause before the noun:

• 先生が送ってくれた = that the teacher sent me
• リンク = link

Together:

• 先生が送ってくれたリンク = the link that the teacher sent me

This is one of the biggest differences from English. In English, the description usually comes after the noun:

• the link that the teacher sent me

In Japanese, it comes before:

• 先生が送ってくれた
  • リンク

Japanese does not use a relative pronoun like English that, which, or who here.

English:

• the link that the teacher sent me

Japanese:

• 先生が送ってくれたリンク

Japanese simply places the clause directly before the noun. There is no extra relative-pronoun word needed.

This is completely normal Japanese structure.

Here, から means from in the sense of starting point or source.

• リンクから記事を読んだ
• read the article from / through / via the link

It shows that the link was the route or source from which the speaker got to the article.

So から is not marking a physical location here. It is more like:

• starting from that link
• using that link as the access point

This is a good question, because both can sometimes sound possible in English as from or with.

• から focuses on the source / starting point
• で often focuses on the means / tool / place

With リンク, から is very natural when you mean:

• I accessed the article starting from that link
• I followed that link to read the article

If you used で, it could sound more like the link is a tool or method, which is not impossible in some contexts, but から is the more natural choice for a link leading to something.

日本語の記事 most naturally means:

• an article written in Japanese

This is different from:

• an article about the Japanese language

If you wanted to say an article about Japanese, you would usually say something more explicit, such as:

• 日本語についての記事

So:

• 日本語の記事 = a Japanese-language article
• 日本語についての記事 = an article about the Japanese language

の links nouns together.

Here:

• 日本語 = Japanese language
• 記事 = article

So 日本語の記事 means something like:

• a Japanese-language article
• an article in Japanese

The の shows the relationship between the two nouns. In this case, the relationship is the language of the article.

This use of の is very common in Japanese.

Because the sentence describes a completed action:

• the speaker read the article

So 読んだ is the plain past form of 読む.

If it were non-past:

• 読む = read / will read / habitually read

If it were ongoing:

• 読んでいる = am reading / have been reading

But in this sentence, the action is presented as something already completed, so 読んだ is the natural form.

It is omitted.

Japanese very often leaves out the subject when it is obvious from context. In this sentence, the person who read the article is understood from the situation, so there is no need to say 私.

So the sentence is naturally understood as something like:

• I read a Japanese article from the link the teacher sent me.

Even though I is not spoken, the sentence is completely normal.

It breaks down like this:

• 先生が送ってくれたリンクから
  • from the link that the teacher sent me
• 日本語の記事を
  • a Japanese article
• 読んだ
  • read

So the grammar pattern is basically:

• [noun-modifying clause + noun] + から + object + を + verb

This kind of structure is very common in Japanese, especially when a noun is described by a whole clause before it.

No. Normal Japanese writing does not use spaces between words like this.

So the natural written form is:

先生が送ってくれたリンクから、日本語の記事を読んだ。

Spaces are often added in teaching materials to make the structure easier for beginners to see, but they are not part of standard Japanese writing.