Tôi cũng nghĩ như thế.

A natural word-by-word breakdown is:

• Tôi = I
• cũng = also / too
• nghĩ = think
• như thế = like that / that way / so

So the sentence is literally something like I also think like that, which in natural English is usually I think so too or I think that too.

In Vietnamese, words like cũng usually come before the verb they modify.

So:

• Tôi cũng nghĩ như thế = I also think that
• literally: I also think like that

This is different from English, where too often comes later:

• I think so too

A useful pattern is:

• subject + cũng + verb

For example:

• Tôi cũng biết. = I know too / I also know.
• Anh ấy cũng thích món này. = He also likes this dish.

Như thế means like that, that way, or so, depending on context.

In this sentence, it points back to an idea that was already mentioned. So if someone says something and you agree, Tôi cũng nghĩ như thế means I think the same way or I think so too.

It is referring to a previously understood opinion, not introducing a new idea.

Yes. Tôi cũng nghĩ thế is very common and natural in everyday speech.

Roughly:

• Tôi cũng nghĩ như thế = slightly fuller, a bit more explicit: I think like that too
• Tôi cũng nghĩ thế = more compact, very common: I think so too

In conversation, Vietnamese often drops words that are understood from context, so shorter versions are very normal.

Yes, very often.

You may hear:

• Tôi cũng nghĩ vậy.

This is probably one of the most common ways to say I think so too in spoken Vietnamese.

Very roughly:

• như thế = like that / that way
• vậy = so / like that

In many everyday situations, nghĩ vậy and nghĩ như thế are both natural. Vậy often sounds a bit more conversational.

Not in this sentence.

Vietnamese can use nghĩ rằng or sometimes nghĩ là when introducing a full clause:

• Tôi nghĩ rằng anh ấy đúng. = I think that he is right.
• Tôi nghĩ là trời sẽ mưa. = I think it will rain.

But in Tôi cũng nghĩ như thế, the idea is already known from context, so you do not need rằng or là.

You are not saying the full thought again; you are just saying I think that too / I think so too.

Sometimes, yes.

In conversation, Vietnamese often omits the subject if it is obvious. So after someone gives an opinion, you might simply say:

• Cũng nghĩ vậy.
• Cũng nghĩ thế.

However, this is more casual and depends on context. For learners, using Tôi is safer and clearer:

• Tôi cũng nghĩ vậy.
• Tôi cũng nghĩ như thế.

Also remember that in real conversation, tôi is not always the most natural pronoun. Depending on age, relationship, and situation, people often use other pronouns such as mình, em, anh, chị, con, cháu, etc.

Not always.

Tôi is correct, polite, and safe, especially for learners. But Vietnamese pronouns depend heavily on who is speaking to whom.

For example, in real life someone might say:

• Em cũng nghĩ vậy.
• Anh cũng nghĩ thế.
• Mình cũng nghĩ như vậy.

So tôi is good grammar and widely understood, but it can sound a bit neutral or formal depending on the situation.

It is generally neutral.

• Tôi gives it a polite, standard feel.
• cũng nghĩ như thế is natural and not especially formal.

In everyday speech, many people would more often say:

• Tôi cũng nghĩ vậy.
• Tôi cũng nghĩ thế.

So Tôi cũng nghĩ như thế is correct and natural, but it may sound slightly more complete than the shortest everyday spoken version.

Nghĩ can be hard because of both the consonants and the tone.

A few key points:

• ngh- is the same basic sound as ng in English sing, but it comes at the beginning of the syllable, which is unusual for English speakers.
• ĩ has a rising, creaky tone in standard northern pronunciation because it carries the ngã tone.

A rough learner-friendly guide is:

• Start with an ng sound right away
• Then say a short ee-like vowel
• Add the correct tone

Even if your tone is not perfect at first, native speakers will often understand you from context, but tones do matter, so it is worth practicing.

Because Vietnamese and English package ideas differently.

English often uses a structure like:

• I think so too

Vietnamese often expresses the same idea with:

• Tôi cũng nghĩ như thế
• Tôi cũng nghĩ vậy
• Tôi cũng nghĩ thế

So instead of looking for a word-for-word match, it is better to learn the whole expression as a natural agreement phrase.

A good habit is to think:

• cũng = adds the idea of also / too
• như thế / vậy / thế = refers back to the idea already mentioned

That is why the sentence feels natural in Vietnamese even though its literal shape differs from English.