Grammar: as or like?
The first thing that you need to know about this case is that not everyone agrees that like and as are interchangeable, as well as that a lot of people use these two words interchangeably without being aware of it.
The second thing to know is that a certain segment of people is dead-set against using 'like' when they believe that 'as' is the correct word. The third thing you might want to know is that these same people can often be guilty of using as instead of because without being aware of it. So, horses for courses.
OK, let's look at this a little deeper.
Case #1: like before nouns
What we are talking about is, essentially, the difference in meaning between Speak to me as a doctor and Speak to me like a doctor. In the first sentence, the person is a doctor and is being asked to speak as one. In the second example, the person is not a doctor but is being to speak like one. Notable books on English usage label this theory a hypercorrection.
Case #2: like before verbs
This is the area that makes some people foam at the mouth. According to the so called rule, like cannot be used as a conjunction before a verb [you can verb like a verb]. This means that you should apparently not say You sing like you just swallowed a goldfish. Instead, it should be something like You sing as though you just swallowed a goldfish.
According to this rule you should never use Say it like you mean it, Sing like me or She stormed out of the house, like she always does.
The thing is, this form of 'like' is not new. We have been using it like this for centuries. It appears in the King James Bible and Keats. Perhaps the most famous person to use like in this way was William Shakespeare, who used it in Macbeth. There comes a point when we have to accept that certain usages become standard if they endure for centuries. And when you do the research, the books on usage usually agree – but not all. It only became a 'problem' from the late 1600s onwards. This 'rule' is frowned on in the US more than it is in the UK.
Case #3: like or such as
The last one to think about with 'like' is – in my opinion – more important than the second case above, and that is to make sure that you don't write like when you mean such as.
What I mean is, don't write The presenters like Max and Stacey when you mean The presenters, such as Max and Stacey. What you will have written in the first example is that the presenters have a liking for Max and Stacey.
About the author
Jesse Karjalainen is the author of The Joy of English: 100 conversations about the English Language, Cannibal – the language and history of the discovery of the New World, and Roanoke – the language and history of Early Colonial America.