Jag tycker att det här är det bästa sättet att lära sig svenska.

Yes — in this sentence, tycker means think in the sense of have the opinion that.

So:

• Jag tycker att ... = I think that ... / In my opinion ...

This is different from some other Swedish verbs that English speakers often confuse with it:

• tycka = to think / feel / be of the opinion
• tro = to believe / think something is probably true
• tänka = to think in the sense of using your mind, considering, planning

Examples:

• Jag tycker att den här boken är bra. = I think this book is good.
• Jag tror att det blir regn. = I think/believe it will rain.
• Jag tänker på dig. = I’m thinking about you.

So in your sentence, Jag tycker att ... is the natural choice because the speaker is giving an opinion.

Here, att means that.

• Jag tycker att det här är ... = I think that this is ...

In English, that is often optional:

• I think that this is the best way
• I think this is the best way

Swedish also sometimes drops att in speech, especially in informal language, but keeping it is very common and completely natural.

So this sentence could also be said as:

• Jag tycker det här är det bästa sättet att lära sig svenska.

But the version with att is very standard and clear.

Det här means this.

Swedish has two common ways to say this:

• det här = this (for ett-words or something general/neutral)
• den här = this (for en-words)

Why det here? Because the word being referred to is understood as sätt:

• ett sätt = a way
• so: det här = this (thing / this way)

Compare:

• det här sättet = this way
• den här boken = this book

Because bok is an en-word, you use den här. Because sätt is an ett-word, you use det här.

They do different jobs.

1. det här = this
2. det bästa sättet = the best way

So the sentence structure is basically:

• Jag tycker att [det här] är [det bästa sättet] att lära sig svenska.
• I think that [this] is [the best way] to learn Swedish.

The first det is part of det här (this).
The second det is part of the definite phrase det bästa sättet (the best way).

So even though the same word appears twice, the grammar is different each time.

Because bästa is the form used before a definite noun.

The adjective bra has these comparison forms:

• bra = good
• bättre = better
• bäst = best

But when Swedish uses best before a noun in a definite phrase, it usually becomes bästa:

• det bästa sättet = the best way
• den bästa boken = the best book

So:

• Det här sättet är bäst. = This way is best.
  (bäst stands on its own)
• Det här är det bästa sättet. = This is the best way.
  (bästa comes before a definite noun)

That extra -a is very common in definite descriptions.

Because sättet means the way, while sätt means a way or just way.

• ett sätt = a way
• sättet = the way

In your sentence, the speaker says the best way, not just best way in a general sense, so Swedish uses the definite form:

• det bästa sättet = the best way

This -et ending is the normal definite ending for many ett-words.

This is a very common Swedish pattern called double definiteness.

When you have:

• a definite noun
• with an adjective before it

Swedish often marks definiteness twice:

1. with an article like den/det/de
2. with the definite ending on the noun

So:

• sättet = the way
• det bästa sättet = the best way

This is normal Swedish grammar, even though it feels strange from an English point of view.

More examples:

• boken = the book

• den röda boken = the red book

• huset = the house
• det stora huset = the big house

So det bästa sättet is exactly what Swedish expects.

It means to learn.

More literally:

• lära = teach / learn, depending on structure
• lära sig = learn
• lära någon = teach someone

This is an important distinction:

• Jag lär mig svenska. = I am learning Swedish.
• Jag lär min vän svenska. = I teach my friend Swedish.

So in your sentence:

• att lära sig svenska = to learn Swedish

The sig is what makes it mean learn rather than teach.

Sig is a reflexive pronoun, like oneself / himself / herself / themselves, depending on context.

In lära sig, it refers back to the person doing the learning.

So:

• att lära sig svenska = to learn Swedish
• literally something like to learn oneself Swedish, though that literal translation sounds unnatural in English

In this sentence, sig is general — it does not mean one specific person. It means someone / people in general.

That is very common in Swedish.

Examples:

• Det är svårt att lära sig svenska. = It is hard to learn Swedish.
• Man måste vänja sig. = One has to get used to it.

So here sig does not point back to jag specifically. It is part of the general expression lära sig.

Because language names in Swedish are usually used without the definite article when talking about the language in general.

So:

• lära sig svenska = learn Swedish
• tala svenska = speak Swedish
• förstå svenska = understand Swedish

You would not normally say svenskan here.

Compare with English:

• learn Swedish
• not learn the Swedish

Svenskan can be used in other contexts, for example when talking about the Swedish language as a subject or system:

• Svenskan är svår ibland. = Swedish is difficult sometimes.
• Min svenska är inte perfekt. = My Swedish is not perfect.

But after verbs like lära sig, tala, förstå, plain svenska is the normal form.

It breaks down like this:

• Jag = I
• tycker = think / am of the opinion
• att = that
• det här = this
• är = is
• det bästa sättet = the best way
• att lära sig svenska = to learn Swedish

So the sentence pattern is:

• Jag tycker att X är Y.
• I think that X is Y.

And here:

• X = det här
• Y = det bästa sättet att lära sig svenska

That makes it easier to see how the sentence is built.

In standard Swedish, det bästa sättet is the normal and correct form here.

Because the noun phrase is definite (the best way), Swedish wants:

• det
  • adjective + definite noun
• det bästa sättet

Leaving out det would sound incomplete or nonstandard in ordinary written Swedish.

So use:

• Det här är det bästa sättet att lära sig svenska.

not:

• Det här är bästa sättet att lära sig svenska.

You may sometimes hear shorter or looser expressions in speech, but for learners, det bästa sättet is the safe and correct pattern.

Yes. Swedish can express this in two common ways:

• det här sättet
• detta sätt

And in many contexts, Swedish also allows the demonstrative after the noun:

• sättet här

But that last one is much less common in this kind of sentence and often sounds more marked or context-dependent.

For learners, the most useful pattern is:

• det här sättet = this way

In your sentence, det här stands alone as this, because the noun sättet is understood from the rest of the sentence:

• Jag tycker att det här är det bästa sättet ...
• I think that this is the best way ...

So yes, Swedish has some flexibility, but det här is the most natural form to learn first.

The main stress would usually fall on the important content words, especially:

• tycker
• här
• bästa
• sättet
• svenska

A natural rhythm might sound roughly like:

• Jag TYCker att det HÄR är det BÄSta SÄTtet att lära sig SVENska.

Unstressed words like att, det, är, and sig are usually said more lightly.

This matters because Swedish often sounds more natural when function words are reduced and the main meaning words are stressed clearly.