I have found many of the topics here very interesting, but would like to share my personal situation, as it is quite specific, to see if you guys have any advice or experiences to share. :)
I am German, and my wife is Hungarian. We live in Sweden (I work in Denmark), and are currently expecting our first child. My Hungarian is very rudimentary, my wife's German is quite good. Nevertheless, our language of communication is English (also the language we work in).
We definitely want to bring our child up with our heritage languages, Hungarian and German. Additionally, there will be a third language involved as soon as the child enters day care, which is possible at age one here. I am a bit torn between Swedish and English as the third language. Normally I would go for the local language Swedish, to enable the child to speak the language of the country it lives in. I really like Swedish as well, and am able to communicate in it at a basic level myself. However, my wife is not that fond of living in Scandinavia, therefore it is hard to foresee for how long we will actually stay here.
English on the other side is generally a very useful language, even if we move somewhere else, as other countries generally have international/English kindergardens or schools. I feel that this decision should be made early on, in order not to confuse the child, or rip it out of a language context and leave it ill-equiped in a third country.
Do any of you have experiences with a similar situation? How did you decide? What challenges did you face along the way?
The last question is a more concrete one: It seems that most parents follow the "one parent one language" approach, which to me makes sense. But how do you handle the language spoken between you and your partner in front of the child, if it is a third one? As described, we usually communicate in English. We could however also switch to German, to keep the languages in the house limited to 2.
This question is a bit related to the previous decision: IF we decide to make Swedish the third language (therefore sending the child to Swedish day care etc.), talking English to each other would mean that the child would actually be exposed to 4 languages. :)
Again, I am happy with any advice or experiences you can share.