Peter speaks both English and Spanish. He sounds like a native speaker in both languages. What is most likely true?

Question

1. Peter learned English first and then learned Spanish during high school.
2. Peter learned Spanish first and then learned English during high school.
3. Peter learned both languages in childhood, during a critical period for language development.
4. Peter spoke a third language first and then was able to learn two more languages in high school.

Answer 1

The most likely true statement is:

3. Peter learned both languages in childhood, during a critical period for language development.

This conclusion is drawn from the fact that he sounds like a native speaker in both languages, which is often indicative of early exposure to both languages during the critical period for language acquisition.