[irrational]

I have some friends where the Mom is Taiwanese and the Father is Peruvian. They have a one and a half year old daughter. The father only speaks Spanish to her and the mother only speaks Chinese to her. But neither parent speaks the other’s language, so they talk to each other in English and all their friends and neighbors only speak English. So far the kid seems to prefer Chinese.

[sigmoid10]

Purely guessing here, but the closest connection a one and a half year old usually has is its mother. Fathers only become more "relevant" to them at 2+ years and people outside the family even later. So it would be normal for the kid to pick up the mother's tongue. But it would be interesting to see how this preference evolves in the coming years.

[irrational]

I'm not sure that is it. The mother is an engineer who works a typical 9-5 job in an office and often travels for work. The father works remote and is home all day.

[sumedh]

> all their friends and neighbors only speak English.

most probably the kid when they grow up will prefer English because their friends speak English.