> Oh no, only 60%? Surely that's plenty for a conversation, no?
It's plenty for communication, not plenty for a conversation.
(It's also a mirror for colonialism, by the way, where the occupied speak the language of the occupier, but the occupiers can't be arsed to learn the language of the occupied.)
It's not even necessarily enough for communication. With the Pareto curve on word commonality it's really quick to get high percentages of vocabulary. But it's the words you don't know on a sentence that are usually the important ones.
Now I wonder if this number, provided it is a real one, went up or down during the last 30 years. I would bet on lower but it's only a gut feeling.