This is a great question.
First off, the question itself implies if you can improve your English by ONLY watching sitcoms… in which case the answer is no, you can’t.
At least not effectively and definitely not very quickly.
Here’s an extract:
You see, any type of passive exposure (i.e., watching sitcoms, reading books, listening to podcasts, etc.) while helpful as a form of extra exposure is not going to do much by itself. But if you love sitcoms, then yes, absolutely, they’re a fantastic source of exposure to English. But again, if you’re going to just use passive exposure, it’s just not going to be enough.
Actually, studies have shown that sitcoms are a good source of learning English in terms of words, phrases, expressions, etc. However, sitcoms (though useful in conversational English) tend to be hyperreal.
One example of this hyperreality is the sitcom “The Big Bang Theory” (which I absolutely loved). They purposely use a lot of scientific jargon because that’s what the show is all about. I mean, even as a native speaker, I had a hard time understanding some of the words because they use a lot of scientific terms. And if you’re watching it thinking, “Oh I don’t understand any of these words, I must be shit at English”, you’re kind of missing the point of the show because it’s designed like that for comedy effect. And another good example would be “How I Met Your Mother”. I mean yes, they do use very conversational English. However, you also have to understand they designed these shows for comedy effect – a comic book or theme park representation of real life.
Another example of a sitcom being a theme park representation of real-life is the show “Emily in Paris”. In fact, it was so heavily criticised because it was SO exaggerated – portraying stereotypical Parisians and their culture to create humour. Parisians in and out of Paris argued that the show is totally exaggerated that it no longer represents what Parisian culture actually is.
And, you know, the point here is yes, absolutely, sitcoms are a great source of exposure to supplement your study time. But sitcoms are also a genre of English unto themselves. And because they’re hyperreal, they’re not actual real-life representations of how people actually speak and behave in the real world.
So, yes, sitcoms are a great source of exposure, but no, you shouldn’t take them too literally.
But ultimately, if you want to improve your spoken English fast, you’re going to need a balanced, structured routine that is to have focused intensive learning and exposure or usage of English in relaxed settings.
This is one of the things that I teach my coaching clients (go here if you’re interested in this).
Hope that helps.
Dr Julian Northbrook