tīngdào zhè gè xiāoxi yǐhòu, wǒ xīnli hěn gāoxìng.

This whole part sets the time/background for the main statement. It means something like after hearing this news.

Chinese very often puts a time phrase or background phrase before the main clause. So the structure is:

听到这个消息以后， = after hearing this news
我心里很高兴。 = I felt very happy / I was happy inside

This word order is very natural in Mandarin.

听 means to listen or to hear in a general sense.

听到 is 听 + 到, where 到 often suggests reaching or successfully achieving something. So 听到 means to hear in the sense of actually hearing / having heard something.

Compare:

• 我听音乐。 = I listen to music.
• 我听到一个声音。 = I heard a sound.

In this sentence, the speaker is talking about the moment they received the news, so 听到 is the natural choice.

个 is a measure word.

In Chinese, when you say this, that, a number, or similar words before a noun, you usually need a measure word:

• 这本书 = this book
• 那个人 = that person
• 一个消息 = one piece of news / a message
• 这个消息 = this news / this piece of news

Even though English does not usually say this piece of news, Chinese often needs that extra classifier word.

Not exactly.

消息 usually means news, information, a piece of news, a message, tidings. It can be personal or general.

新闻 usually means news reports or the news in the media.

So in this sentence, 这个消息 sounds like this news / this piece of news, possibly something the speaker personally heard. If you said 这个新闻, it would sound more like this news report/story.

以后 means after or afterward.

In 听到这个消息以后, it marks that what follows happened after hearing the news.

You can think of it as attaching to the earlier phrase:

• 听到这个消息以后 = after hearing this news

A shorter version is also common:

• 听到这个消息后

Both are natural. 以后 is slightly fuller and often a bit more conversational.

Both are correct, but 心里 adds nuance.

• 我很高兴 = I am very happy.
• 我心里很高兴 = I feel happy inside / in my heart I am happy.

心里 literally means in the heart / in one's mind / inside. It emphasizes an internal emotional feeling.

So the sentence with 心里 feels a little more expressive and personal.

This is one of the most common Mandarin questions.

In Chinese, when an adjective serves as the main predicate, it is often preceded by 很, even when the meaning is not strongly very.

So:

• 我很高兴 often just means I am happy
• not necessarily I am very happy

If you say 我高兴, it can sound incomplete in many contexts, or it may suggest contrast. So 很 is often there because Chinese prefers an adverb before the adjective predicate.

Of course, sometimes 很 really does mean very. Context decides.

Yes. That is completely natural.

• 听到这个消息以后，我很高兴。
• 听到这个消息以后，我心里很高兴。

The version with 心里 adds a more inward, emotional tone. The version without it is simpler and more neutral.

Usually it stays attached to the action it follows.

Natural:

• 听到这个消息以后，我心里很高兴。

Also natural:

• 我听到这个消息以后，心里很高兴。

Less natural or different in meaning:

• moving 以后 too far away from 听到这个消息

A good habit is to keep 以后 right after the event it refers to.

The comma separates the background/time phrase from the main clause.

So:

• 听到这个消息以后， = after hearing this news,
• 我心里很高兴。 = I felt very happy.

In Chinese writing, commas are often used after introductory phrases like this. It helps readability and reflects the natural pause.

In Mandarin grammar, 高兴 is usually treated as an adjective meaning happy/glad.

But Chinese adjectives can function directly as predicates, which is why they can look a bit like English verbs in translation:

• 我很高兴。 = I am happy.

So although English uses am, Chinese does not need a verb like to be here.

Yes, both often include a neutral-tone syllable in normal speech.

• 这个 is commonly pronounced zhège
• 心里 is commonly pronounced xīnli

That means the second syllable in each word is often lighter and shorter than a full tone.

So in natural speech:

• 这 = fourth tone
• 个 = often neutral here
• 心 = first tone
• 里 = often neutral here

Learners often pronounce every syllable with a full tone at first, but using the neutral tone will make your Mandarin sound more natural.

Sometimes, but the meaning changes slightly.

• 听到这个消息以后 = after hearing this news
• 知道这个消息以后 = after finding out/learning this news

听到 focuses on the news being heard.
知道 focuses on coming to know it.

If the idea is simply that the speaker learned the news, 知道这个消息以后 can work. But if the original sentence specifically says they heard it, then 听到 is better.