Difference between て-form and と/や for connecting adjectives/verbs

Question

I was reading about the て form and trying to understand it, then I came across some sentences using て form and a question came into my mind:

What changes if instead of using the て form for all verbs and adjectives, と/や are used?

Example:

日本語クラスは簡単で面白くて楽しい。

Couldn't it be rewritten like this?

日本語クラスは簡単なと面白いと楽しい。

Or are と/や used only for "things", while the て form is used for words?

Also, I read that て form is used to connect the contents of the sentence. But in the example I rewrote above, isn't it clearly connected?

Answer 1

と -in the sense of A and B- and や can only be used to connect nouns or noun-phrases, but they cannot be used to connect adjectives and verbs.

Therefore this sentence would be wrong:

x 日本語クラスは簡単なと面白いと楽しい。

But you can say this:

○ 日本語クラスといえば、「簡単な」と「面白い」と「楽しい」という言葉を思い出す。

Regarding Japanese classes, I think of [the words] "easy/simple" and "interesting" and "fun".

Here the words are only mentionted, effectively they become the noun the word X.

The te-form can be used to join sentences, phrases or verbs/adjectives. For illustration, another example with the te-form:

早起きして体操をした

本を読んで感想を書く

Note that the te-form has got a few other usages as well, such as implying a causal relationship:

金が無くて行かれない

Finally, it should be mentioned that と can be used with verbs as well, but that is a different usage and coonects phrases, but not nouns:

電気を消すと暗くなる。 (If/When lights are turned off, it gets dark.)

家に帰ると手紙が来ていた.　(There was a letter waiting for me when I got home.)

どうして節電しないといけないの？ (Why do [I/we] need to save electricity?)