RE: Q of where someone lived during each stage of their educational(?) life, can we have people include "amount of exposure to each of their acquired languages?" for each timeframe?
regarding question 1 and 2, formal education as prof. nakamura said is when there was a person teaching some language with the purpose of teaching it. so i think that would include 塾 and tutors.
with the question of where people lived in certain stage, i definitely think the exposure element should count. ていうか、for the surverys, the wordings are really tricky to come up with.
あと、これはPre survey後のインタビューに影響が出ないように、Survey questionsは英語と日本語の両方で一応書いたほうがいい気がする。
実際影響するかはわからないけど、両国語でかくとthey may feel free to use whichever the language they feel comfortable with.