Why is '' speaking five languages'' a general ability? I saw these examples in the grammar book, it says:

1.My grandfather could speak five languages.

2.We were completely free. We could do what we wanted.(=we were allowed to do...)

The explanation to the first example is we also use could to say that somebody had the general ability or permission to do sth. So now I am wondering about what '' general ability'' really is, does it mean ''ordianry abiltiy"? if it does, I believe from the view of most people, a person who can speak five languages is more capable than an ordinary person.

The explanation to the second example is even more ridiculous from what I can see, because it happened in the past, so obviously we should use "could" instead of "can".

Many thanks for your answers.
Apr 5, 2018 2:37 PM
Comments · 13
I think speaking 4 languages is a major ability so I guess 5 earns you a promotion to general!
April 5, 2018
Here’s what you need to know in order to understand the grammar:
It’s a general ability because you’re not referring to a specific situation. We could also say that you “knew how to” speak five languages.

If you can speak five languages, but there’s nobody to talk to (or they refuse to talk to you), then you can’t really have a conversation, can you? Or the authorities might prevent you from exercising your freedom of speech *on a particular occasion.* Or you might have a case of laryngitis, interfering with your ability to speak. For that matter, you could be asleep. In affirmative past-tense statements, “could” is not used to refer to these specific situations — use “to be able to” instead.
April 5, 2018
I use the distinction of "ability" and "possibility".  I think the word "general" was not used clearly enough in that explanation because there was no contrast with "specific ability". However, leaving that to one side, the grammar rules are accurately explained.
April 5, 2018
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Language Skills
Chinese (Mandarin), English, German
Learning Language
English, German