In Swedish, the word “think” has three significantly different meanings (at least three, there might be more meanings that I can’t think of right now). If you mean that your mind is occupied with the act of thinking about something, as in “ponder”, you say “jag tänker”, whereas if you use the word think to express your opinion about something you say “jag tycker”. The third meaning is “I believe”, which is “jag tror” in Swedish.

To make things complicated, even if “att tänka”, “att tycka”, and “att tro” may all be translated with “to think” in certain contexts, they also quite often mean something else than “to think”. Below are some sample sentences using the words “tänka”, “tycka” and “tro” in various ways.

Vad tycker du?
What do you think (as in “What’s your opinion?”)

Tror du på spöken?
Do you believe in ghosts?

Vad tänker du på?
What are you thinking about?

Jag tror dig.
I believe you.

Jag tror på dig.
I believe in you.

Or, in fact, also used for “I believe you” (as in “I believe that you are telling the truth”)

Vad tycker du om?
What do you like/enjoy?

Vad tycker du om att göra [på fritiden]?
What do you enjoy doing [in your spare time]?

Vad tycker du om U2? (Also “Vad anser du om U2?”, and in spoken language sometimes “Vad gillar du U2”, but the latter one is not considered “correct” Swedish)
What do you think about U2?

Tycker du om U2? (Also “Gillar du U2?”)
Do you like U2?

Note that in the meaning “do you like X”, you need to put the stress on the word “om” if you use “tycker du om X?” rather than “gillar du X?”. The same goes for “vad tycker du om”, as in “what do you like/enjoy”, i.e., you stress the word “om”. In the meaning “what do you think about X”, you instead stress either the word “du” (what do YOU think about X”), “vad”, or “X”, but definietly not “om”.

Swedes have a weird habit of using the phrase “jag tror inte det” (and similar forms) when we mean “no” and want to sound polite. Directly translated to English, I think it sounds rude rather than polite (although I might be wrong — English is not my native tongue after all), but in Swedish it is a polite response.

Seller: “Vill du köpa nåt?”
Passenger: “Jag tror inte det”

“Would you like to buy anything?”
“I don’t think/believe so.”

I once heard, sitting on a bus (long distance), the guy selling sandwiches, beverages and snacks onboard replying “believe is something you do in church, do you want anything or not??” when hearing “I don’t believe so” in response to his question if a pontential customer wanted to buy anything. So when we start to think about the expression “jag tror inte det”, we obviously also see that it’s a strange way to say no. But it’s nevertheless widely used.

Hur tänker du nu? 

Literally “How do you think now?”, actually meaning just that (although it sounds rather ridiculous in English). It’s mainly used when someone doesn’t understand how someone else came to a certain conclusion. So he/she is indeed interested in understanding the process of thinking in the other person’s head.

Note that “Hur tänker du nu?” usually, but not always, implies that you disagree, at least to some extent. Especially if you stress the word “hur” (“how”) when you speak the sentence. Or it could just mean that you are totally lost, but not necessarily because the person you are listening to is wrong, but because you cannot follow his/her logic (for any reason). When used with the latter purpose, the word “nu” is often stressed.

In the sentences below, “jag tänker” means “I imagine” or “I have in mind”.

Jag hade tänkt mig en liten tårta, annars blir det nog för dyrt.
I had a small cake in mind, otherwise it will probably be too expensive.

Jag tänker mig en liten tårta för att hålla kostnaden nere.
I have a small cake in mind to keep the cost down.

Some examples using the imperative form of “tänka”, i.e. “tänk”:

Tänk att du alltid ska ha rätt!
(Loosely translated) You’re right, as always!

Tänk, imorgon har vi varit gifta i 20 år.
Realize this, tomorrow we’ve been married for 20 years.

Tänk vad roligt vi ska ha det på Disneyland!
Imagine how much fun we’ll have at Disneyland!

Tänk först, handla sen.
Think first, act later.

Tänk igenom ditt svar noga/noggrant.
Thoroughly think your answer through.

I wonder how we (Swedes) think about these things compared with people who have English as their mother tongue, or any other language that has the same word for all meanings. Research shows that our languages shape the way we see the world, and I’m sure it does.

As always, don’t hesitate to comment if you have questions or thoughts about this subject, or want me to give examples of the usage of a particular word.