@raggedyman So - we implement a kind of OPOL hybrid at home (we’re actually a trilingual family living in a country which speaks my native language, where I also do more of the childcare so OPOL wasn’t appropriate) But first of all I want to say - I’ve seen several studies which have shown that the most important factors in helping children gain fluency in a language is amount of exposure and opportunities to use the language, I can probably dig out the citations if you’re interested but don’t have them off the top of my head. So it’s about working out strategies which are going to help achieve adequate exposure for your children and your family situation, and for some parents OPOL ticks that box and for others it doesn’t work as well! There are of course other factors but I haven’t seen any research which specifically show better results from OPOL than any other method, with the same level of exposure.
Advantages of OPOL from my perspective:
1 - Quality of the language input: if you’re doing OPOL it’s likely each parent is native speaker in the language so the child is only hearing correct and natural language. Language complexity will likely develop naturally as the child grows up and it ensures lengthy and rich conversation in the target languages
2 - providing both parents are spending similar amounts of time with the children then it ensures roughly equal exposure
3 - it provides children with the incentive to speak in a language - if conversations with Mum are only ever in Japanese, (as they get a bit older and become aware of what language they are speaking) they are more likely to make an effort to speak to Mum in Japanese even if they have to think a bit more to phrase it, because they always interact with Mum in Japanese, and Mum is more likely to model language in Japanese/notice language gaps quickly than if changing between languages all the time
4 - depending on the relative fluency in the language it’s more natural and will lead to a a lot more cultural awareness and sharing
5 - clear distinction from the get go that these are different languages or that you’ll say the same thing in different ways to different people.
6 - avoiding mid-sentence mixing, this may or may not be a problem for yourselves but language switching is fine for teaching children, providing you’re both able to form complex and accurate structures in both languages, but if one (or both of you ) isn’t, then you could be inadvertently passing on this hybrid language where you throw in words/idioms or structures from your native language to the child
Disadvantages of OPOL (again from my point of view):
1 - Depending how your family life is divided up it means that children may miss out on exposure to a language in one area, because that parent isn’t usually home or involved in that type of activity
2 - if you aren’t spending equal amounts of time with the children, then you’re inadvertently exposing the child to much more exposure to one language than another
3 - conversations are more natural when you’re mixing languages - depending on how you approach OPOL the child might well be used to having a conversation in two languages at once, but I can never fully get my head round how group conversations work using a strict OPOL method unless both parents are fluent. And if parents are used to mixing languages between themselves it’s going to feel a lot more natural for having whole family interactions - which I think is a big thing.
4- and I think this is quite a huge factor in favour of both parents speaking both languages, if you and your wife are living in, for example, a Japanese speaking country. The adaptability to decide that overall your daughter is having more exposure to Japanese, and you need to speak in French 70% of 100% of the time at home (or vice versa) gives you a lot more flexibility and more certainty of your child attaining a good level of French by adulthood. For example, you can notice that your child is reluctant to speak in Japanese and decide to spend two weeks speaking in nothing but Japanese to give her a boost.
It’s absolutely normal for children to speak this kind of ‘creole’ at that age when they’re growing up bilingual, I wouldn’t worry about it too much, but depending on the language outside of the home, it’s quite possible that she’ll end up favouring one language over another, but by both parents speaking both I think you’re giving yourself some extra options to combat that.
To give you an example of my own perspective - we live in English speaking country, with some english speaking childcare, we speak in Spanish between the two of us and when we are together as a family, I speak half in spanish half in English when I’m alone with the children and my husband speaks in Catalan with the children when he’s alone with them (or at least means to but sometimes I don’t think he even notices if he speaks spanish or Catalan).
I’d say both children seem to understand all three languages, but they mostly speak spanish or English, it’s disappointing as eldest daughter originally spoke all 3 when we lived in Catalonia but as her exposure decreased so has her usage; it’s not a major concern for us though as she still understands and it is closely related to Spanish so we figure she will be able to pick it up easily later. I worry that at almost 4, my daughter should be able to distinguish better between who speaks Spanish vs who speaks English, but I think due to the mixing I don’t know if she thinks everyone is multilingual or if she’s not worked out that they’re different languages - but compared with other bilingual families I know she definitely mixes more and doesn’t distinguish as well who to speak which language to. My eldest daughter understood the Catalan word for water as specifically bath water for a time because her Dad does bath time but it must not have been used out of that context very much, that was the main one but I’ve noticed a few differences in her vocabulary just through what she’s been exposed to through what her Dad does with her vs what I do. I decided from the get-go even when living in Catalonia to not speak to my children in Catalan, because I’m not completely fluent and do use translated spanish structures or might throw in a spanish word when I get stuck, but this may be politically motivated depending on your point of view because amongst Catalan native speakers they are very aware of the influence of Spanish on their language, but it may not seem like such a big deal if you’re talking about languages which don’t have such a charged history of oppression, because nobody ever had a problem understanding me in Catalan but it’s quite a hot topic politically so I decided to steer clear. (Although no doubt in a few years if the girls don’t speak Catalan properly I’ll get in trouble for not using more Catalan at home!)
Ultimately, I think for everyone raising bilingual or multilingual family it’s about weighing up the pros and cons of each method and doing what will work best for you as a family!