Has anyone realised their knowledge is limited to one language usually.

Nah not really, I spent a year in South Korea when i was 16, and pretty much all the memories I have from that are in Korean.

I speak 3 languages, and I can't say I think in a particular one. So imho, people think in terms of ideas/images but not int terms of series of words.

Wrong.

you can obviously conjure up an image in your head, such as of a cat or dog. But the definition of thinking is talking to yourself and you need a language to talk to yourself in.

Well to be honest you can't have memories in a language. Your memories are "images/passages of film" which can be put into a language by the brain. This is because the brain links words to images. These images in your brain come from the senses, i.e. reality.

Language and memory aren't bound in my brain, it's pretty random. Sometimes I remember speaking English while I actually spoke French or vice versa, or even remember somebody speaking in a language they don't speak. Sometimes I don't remember what language was spoken at all, just the meaning.

Not it's not.

How would children learn to speak if they couldn't think beforehand? Are you suggesting babies can't think?

That is a whole other story. You have to realise I'm talking about adults. babies are different, no one really knows how babies think. Do you remember thinking before you knew a language?

And children learn to speak by listening and relating an object in real life to a word in that language. Like you will see little kids see a car and shout out "car".

Of course I don't remember that far back.

The child sees the object and relates it to a word. To be able to relate it to the word they need to be able to recall what the object is - therefore think about it, even if it's just an image of the car.

Don't people find it interesting that all your memories, thoughts and knowledge is limited to one language usually. Like most people in the uk are taught all their subjects in English.
Therefore your whole world revolves around that language, quite interesting tbh.

you can obviously conjure up an image in your head, such as of a cat or dog. But the definition of thinking is talking to yourself and you need a language to talk to yourself in.

So you are suggesting that thinking only can occur once you have the language down pat enough to speak the thoughts?

Not my experience at all.

I concur!
I don't think I think in any language when, for instance, solving an equation. But it is most certainly 'process of thinking' at its best.