"I do not think these languages are familiar to me."
Translation:Tôi không nghĩ các ngôn ngữ này quen thuộc với tôi.
In an earlier exercise, I recall
"We learn languages because we want to have a flexible career"
We were told "nhưng ngôn ngữ' was not necessary as 'languages' need not be made plural or countable.
But lo and behold, leave it out here, and you get zapped. Both can't be right.