Continuing the discussion from My personal wish for the "Ransome uncensored" update:
So, @milanfahrnholz was wondering if, since the seventies, there was an increase of the usage of the word “alien” as a synonym of “extraterrestrial being”.
Let me introduce you one of the most time-sucking nerdy/research tools on the Internet: Google Books Ngram Viewer.
Basically, Google has digitized a lot of books and has analyzed their text, providing a tool that lets people to search for words in the books and to observe how language has changed over time. The assumption is that when language changes, it also changes in the text of the books.
DISCLAIMER: Google Ngram Viewer is not a very good tool to study polysemy and I tell you in advance that at the end of this post I will not be able to give an answer to the question. But if you are curious about Culturomics, maybe you’ll find the following research interesting nonetheless.
Let’s start with a first chart about how much the word “alien” is used as a noun and how much it’s used as an adjective.
Now, let’s focus on the noun “alien” and observe which adjectives are usually used before it:
Hmm… “nonresident”, “resident”, “illegal”… it’s clear that most of the adjectives are not associated with the meaning “extraterrestrial being”. But this observation could be misleading, because the fact that a word is used with a specific meaning in one context tells you nothing about how its other meanings have been used along the years.
So, let’s try some word voodoo to focus a little more on the noun. For example, do people use the word more as a noun than as an adjective? I can apply arithmetic operations to words and I can divide noun/adj:
It seems that the usage of the word “alien” as a noun has increaded in the last decades, starting roughly in the seventies.
Still, the chart doesn’t tell us if the usage of the specific meaning “extraterrestrial being” has increased. It only tells us that the usage of the noun (with all its meanings) has increased more than the usage of the adjective.
What can I do to focus more on the “extraterrestrial” meaning? Well, Google Ngram Viewer is not a tool to analyze texts from a semantic point of view, but I can make some assumptions that can help my research.
For example I can assume that the usage of the word “alien” in the books marked as “fiction” has been different from the usage of the same word in all kind of books. The following chart seems to validate my hypothesis, especially if you focus on what has happened from 1960:
In fiction, the usage of the noun “alien” has rapidly increased since the middle sixties, while the same noun has seen a similar increase only after the eighties, if you consider all the books.
My interpretation is that during the sixties something has happened to the usage of the noun “alien” withing the fiction niche. We can’t exclude that this peculiar peak had nothing to do with the meaning “immigrant/foreigner” but I would say that it’s more probable that in the fiction context the word has been used more with the meaning “extraterrestrial being”, mainly because fiction books include science fiction books.
On the other hand, the peak that you can observe in the general corpus, starting in the eighties is not related to an increase of the meaning “extraterrestrial being” (because in this case the peak would have been observed also in the fiction books index) but because the topic “immigrant/foreigner” has become more discussed and, consequently, the word “alien” more mainstream.
Another way to observe the fact that the word “alien” has become more mainstream since the eighties, is to do a simple division between the usage of the noun in the fiction book and the usage of the word in all the books:
The chart confirms that the noun “alien” was more fiction-related until the late seventies but it has become more mainstream since then.
If you dig a little more you find that the peak in the general corpus started in the eighties was mainly associated with the usage on the expression “the alien’s” and if you want to see the words that usually follow this expression, you immediately understand the context of this modern usage of the noun “alien”:
To sum it up: in the sixties and seventies the word “alien” as “extraterrestrial being” has been more used in fiction.
If you want to play a bit with Google Ngram Viewer, be aware that its query syntax is a bit complex and that you might want to have a look at this guide.
…I’m an alien, I’m a legal alien…
It´s no fun being an illegal alien 
…
