"The English language has changed over time" OR "The English language has been changed over time"

Question

Are this two sentences the same?

1. The English language has changed over time.
2. The English language has been changed over time.

Also, which one is correct?

1. How the English language has been changed over time?
2. How has the English language been changed over time?
3. How has the English language changed over time?

Are they the same?

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I watched a video about English Language history, and a man who was native speaker said: "How has the English language changed over time?" But, why didn't that man use the word been? I mean: "How has the English language BEEN changed over time?"

Answer 1

Change is a labile verb, meaning that alongside its transitive use there is an intransitive use in which the transitive object becomes the subject. This latter use is sometimes called middle voice:

1. As an intransitive verb, its subject undergoes the change:

   The English language has changed over time.

2. As a transitive verb, its object undergoes the change:

   Someone has changed the English language over time.

   Now we have someone causing the change.

3. And when you passivize the transitive version, you end up with your been sentence:

   The English language have been changed over time by someone.

   We still have someone causing the change, but the by someone phrase has been omitted.

So although both sentences work, the been sentence implies that it's been changed by someone. (Or something—see Esoteric's comment below.) And although this is perfectly grammatical, it may or may not be what you want to say.

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You also ask about three sentences:

1. How the English language has been changed over time?
2. How has the English language been changed over time?
3. How has the English language changed over time?

We've already covered the difference between sentences 2 and 3, so I'll just talk about sentence 1. This sentence has the form of an interrogative clause, but main clause interrogatives are usually marked by Subject-Auxiliary Inversion. This isn't, so it doesn't work as a complete sentence (except as perhaps an echo question or the like):

how [the English language]_subj has_aux been changed over time

It does work as a subordinate interrogative clause:

I wonder [how [the English language]_subj has_aux been changed over time].

It works as a complete sentence if we invert the subject and auxiliary. If we do that, we end up with sentence 2, which is perfectly grammatical:

How has_aux [the English language]_subj been changed over time?

Though note, as previously discussed, that this question implies it's been changed by someone, which, depending on context, may not entirely make sense.

Answer 2

As Catja has mentioned in the comments; been would imply a change as the result of a specific person(s), event, or item. Leaving out the been encompasses all changes both natural and forced.

To answer the first question: Yes they both mean the same, but the first is more generally acceptable.

Second question: Sentences 2 and 3 are correct, but sentence 2 implies that you are asking about forced changes only, where as sentence 3 is asking for all changes. So if you are asking for all changes to the English language only 3 is correct.