In our bilingual journey, I made two observations that are likely different from the commonly used pedagogy for Chinese immersion schools.  The following assumes that the goal is IRL level 5 (native level) for English and IRL level 3 or greater for Chinese by end of high school.  I appreciate any feedback.

1.  Reading and writing.  Get reading proficiency high first, so that the child can enjoy entertaining readings in Chinese around the time he develops stronger and stronger English reading.   Enjoying CLE (Chinese language ecosystem) in greater depth does not require writing but requires decent reading proficiency.  Since all these reading practices takes time, which is often the most precious resource, I recommend not spending nearly as much time doing writing early on.  Also, the reading part of the CLE would be mostly narrative readings.  When the child can read youth and/or young adult novels proficiently hopefully by/in middle school, start doing more expository readings and then start doing more writing and typing.  Composition is the typical “highest order” skill, used to narrate, explain, or persuade.  I would be more than happy if my children can compose decently well in Chinese by typing instead of writing everything out.  But of course, they need to know how to write basic characters and how to write any characters presented with the correct stroke order.

Don’t get bogged down with trying to learn much reading and writing at the same time and then end up with only IRL level 1-2 on both end due to lack of time.  Get reading proficiency high to IRL level 3-4 as soon as possible and then come back to work on writing.  One’s writing proficiency is almost never as good as one’s reading proficiency; so, getting reading proficiency high first.  Then, the child will have a much higher chance of writing Chinese using the correct Chinese syntax and expression, rather than “Chinglish”.

However, if the community ecosystem has a strong Chinese language presence (not saying it is dominant) with decent CLE built in and the overarching schooling assessment takes bilingual education into account, such as in Singapore, then simultaneous emphasis on reading and writing can work well.

2.  Subject language learning.  These are the more “technical” vocabulary and expression in different subjects, mainly science and social studies.  The child’s Chinese proficiency almost always lags behind his English proficiency, particularly past third-fourth grade.  Not to mention that annual standardized testing and assessment are mostly done in English.  So, it makes sense to learn these subjects using the more proficient language – English.  It’s much faster too, as the child won’t be bogged down by inadequate Chinese proficiency.  After a year or two, come back to do some reading of these subjects, in Chinese.  This second part is to learn the terminology in Chinese but not the subject itself, since the child already knows the subject in English.  In this fashion, we separate subject learning from Chinese language learning and use the English language ecosystem to our advantage.