Based on my family's history, my guess is that success rates are generally higher for the first kids.
My mom's side of the family is from East Friesland. My maternal grandfather was born in the US, but didn't speak any English when he started school. Grandpa was certainly fluent in English by the time I came along, and I presume he was reasonably fluent in English by the end of grade school. My maternal grandparents were bilingual, but decided to speak "Pig German" at home and let their kids learn English in school. My mom's oldest brother learned English the same way Grandpa did. Mom's older siblings spoke English enough that Mom never really learned to speak German. Grandma and Grandpa would speak to Mom in German, and she'd reply in English.
Though, plenty of German vocabulary made it into Mom's lexicon. I think I was in late middle school or early high school when I realized wunderbar wasn't an English word.
My oldest son is more fluent in Thai than English, where my wife does a good job of speaking almost 100% Thai to the kids. We'll see how the twins do once they start speaking and when the oldest starts going to preschool. My guess is that the oldest will speak primarily English to the twins, making it harder for them to pick up Thai.
My mom's side of the family is from East Friesland. My maternal grandfather was born in the US, but didn't speak any English when he started school. Grandpa was certainly fluent in English by the time I came along, and I presume he was reasonably fluent in English by the end of grade school. My maternal grandparents were bilingual, but decided to speak "Pig German" at home and let their kids learn English in school. My mom's oldest brother learned English the same way Grandpa did. Mom's older siblings spoke English enough that Mom never really learned to speak German. Grandma and Grandpa would speak to Mom in German, and she'd reply in English.
Though, plenty of German vocabulary made it into Mom's lexicon. I think I was in late middle school or early high school when I realized wunderbar wasn't an English word.
My oldest son is more fluent in Thai than English, where my wife does a good job of speaking almost 100% Thai to the kids. We'll see how the twins do once they start speaking and when the oldest starts going to preschool. My guess is that the oldest will speak primarily English to the twins, making it harder for them to pick up Thai.