This is a great article that explains, from the research, why no one method is a guarantee of bilingual success. When I do parent seminars we talk about this a lot. Being an OPOL family doesn’t automatically mean your kids will be bilingual. Having a minority language at home does not automatically mean your kids will be bilingual. Outside of true bilingual communities, successful child bilingualism happens when you pay attention to ensuring adequate quantity and quality of input, and provide meaningful opportunities for language use.
It won’t happen by itself – you need a plan!
A question of primary importance concerns the type and amount of language input the child will receive, mainly from his/her parents but also from other sources.
The Languages you Speak to Your Bilingual Child | Psychology Today.
on raising bilingual children 
What a pity, I cannot read this in Qatar (the site has been blocked?). Is there another way to read it? thanks!
I could email it to you if you send me your email address? Mine is eowyn@crisfieldeducationalconsulting.com
I couldn’t agree more. Parents absolutely have to have a plan and commit to it, especially for the majority language. Working with multilingual families, I constantly see children who understand, but can’t speak, a minority language.
You are right about the “plan” and I would underline as well “the parents” – it has to be a plan both want to follow and both give their energy towards.
Definitely – That is why I only do Family Language Planning with both parents – even when they are separated or divorced. Both parents have to agree on the approach to bilingualism and the plan to get there.
What an interesting article!