【新生児は地球上の全言語の音を区別できる　約600の音節と200の母音　ですが、最初の誕生日までに自分の母国語で使われない音を脳がフィルタリングし、外国語の訛りは成人学習者にとってほぼ必然的なものになる】

TIL that newborns can distinguish the sounds of every language on Earth, about 600 consonants and 200 vowels, but by their first birthday, their brain has already filtered out sounds not used in their native language, making foreign accents almost inevitable for adult learners.