While researching my topic, I learned a lot about raising children bilingually, and many things I thought I knew about the subject were proved wrong. For example, I used to think that as longs as each parent keep strictly to one language, then there is no reason why the child shouldn't become bilingual. I assumed that's the way it was, because that's the way it had been in my family. What I didn't take into account, however, was that my family lived in an entirely bilingual setting - a bilingual country, and a small, bilingual town, where the country's minority language was actually a majority language*. So what my family had was actually what many researchers call the ideal setting, where the minority language is the common language of the family (i.e. Finnish was the minority language in my town, but the common language at home) - with an added bonus of us living in a country where that "minority" language was actually used everywhere outside my hometown.
Wow, this is getting really confusing, but my point is this: when I grew up, I received a lot of input in both of my languages, both at home and outside of it, which is really as good a situation as you can possibly have. It is also quite an uncommon situation outside of bilingual areas. So, someone who's moved to another country, and has a partner from that country, will most likely have nowhere near as good a situation (linguistically speaking) as my family did. Hence my assumption that it would be enough for, for example, a Finnish woman living in the UK to simply stick to speaking Finnish to her children in order for them to learn it perfectly was way off - it really takes a lot more work and determination than that, and even then there is no certainty about the outcome, as many factors play a part.
As well as learning about raising bilingual children, my research also taught me some things about myself and my own situation, and it seems that this has been an ongoing process, as I had an epiphany of sorts yesterday. I tend to mix my languages a lot - my Swedish is spiced with Finnish and English words and expressions, and some English is added to my Finnish - because I know that everyone can understand me, and I either can't think of the right word fast enough, or there is a better way of saying it in another language. Obviously I don't do this when speaking to monolingual people, but most people I know speak at least two languages, so it's never a problem. However, I have friends who grew up speaking only Swedish or Finnish, and they don't tend to mix languages as much as I do, which sometimes makes me feel like I'm not quite at their level linguistically. In the literature on bilingualism, however, it was clearly stated that this mixing of languages (i.e. code-switching) isn't a sign of lacking linguistic abilities, but simply a communication tool used by bilinguals. So the fact that I'm mixing languages more than my friends are (even though they all speak at least two or three languages now) is just because I grew up with two languages, and got used to making the most of them, so now I'm doing the same thing with all my languages.
I'm looking forward to taking my research to the next level with my master's thesis this autumn - I'm sure I'll learn loads more about the topic in the process.
*Confusing? Basically, the majority of Finns speak Finnish, and Swedish is the minority language, but in my home town Swedish is the majority language, with a minority of Finnish speakers