When an older sibling starts school: what changes

The sources read for this site describe a mechanism, not a measured result. King and Mackey, in The Bilingual Edge, relay a parent's account of two things that happen together when an older child starts school: the child brings home more of the community language, and the school hours free up time for one-on-one attention to the younger child. The sources do not say how large either change is, and they do not test whether acting on it changes any outcome.

What the book describes

In chapter 5, the book quotes a parent who says the older sibling's arrival at school "pollutes" the home environment for the younger one. The word is the parent's, not a measured term. The picture is plain: the older child spends the day in the community language and carries it home, in words, phrases and play.

The same chapter points to the other half. The older child's school hours become hours a parent can spend one-on-one with the younger child, which was not possible before. The app's notes record this as a parent's interview in the book, so the strength is REPORTED.

Chapter 6 adds context. For a family where both parents are native speakers of the heritage language, King and Mackey say the community language has a way of seeping in from everywhere else. That is their own statement, read in the book (VERIFIED), and it explains why the school start is one more route in, not the first.

What the sources do not say

• How much more community language comes home, or for how long. No figure appears in the notes.
• That a family who acts on the freed-up hours ends up with a better result. No source read for this site tests it.
• Anything about the school itself: its language, its hours, or the age at which it starts where you live.

A separate finding is easy to mix up with this one. Shin, as King and Mackey report it, found that 79% of first-born children spoke Korean with their parents, against 66% of second-born and 43% of third-born, in 204 Korean-American families. That is about birth order, not about the school start. It is REPORTED, a secondary citation, and the book gives the study's year as 2002 in one place and 2005 in another. The notes leave that open, and so does this page.

What the app does with it

For a child in a family, the app does not ask whether an older child is in school. It works out a flag from birth years: true if a sibling born in an earlier calendar year is currently age 5 or older. Age is this year minus the birth year, unless a birth month was entered, in which case it is years completed, counting from the 1st of that month. It is an approximation. With no birth month, a sibling born late in 2021 counts as 5 in October 2026 whether or not school has started; with December 2021 entered, the same sibling counts as 4. The age of 5 is a fixed default, not what your school system uses. Siblings born in the same calendar year do not count. On the standalone plan page there is an optional question instead: where your child comes in the family. For a second or later child, a box appears: "An older brother or sister is 5 or older". That one is your own statement, with the same rough 5.

ILLUSTRATION with invented inputs: a 4-year-old, Spanish at home, English outside, 30 minutes a day, a conversation goal, one parent at home. The plan is 14 minutes of talk, 7 of reading, 5 of songs and 4 of a family ritual, 30 in total. With the flag on, the minutes are identical. The only change is one extra tip, taking the list from 4 tips to 5.

The tip says the older child brings home more community language, that the school hours free up time with this child, and that it is worth using some of that time for the heritage language. Its last words, that this does not happen by default, are the app's own judgment. The sources read do not test it (UNVERIFIED). The tip appears when the flag is on: on each child's plan page in a family, and on the standalone plan page when you tick the box.

A practical way to use the change

1. Pick one recurring slot while the older child is away, such as the morning before pickup. Fixing the slot is advice, not a finding.
2. Use the slot for what the plan already lists: talk, a short book, a song, in the heritage language.
3. Expect the older child to bring community-language words home. The book's account treats this as part of the transition, not as a failure of the home.
4. The flag is read from the children's birth years each time the plan is opened, so a plan saved before the older child turned 5 picks up the tip on its own.

What is still unknown

• The size and length of the shift toward the community language after the school start.
• Whether using the freed-up hours for the heritage language changes what a child speaks later.
• Whether the app's age-5 rule matches your family's real school start.