Anyone who has watched American television, or who has listened to American
teenagers 'speak', has probably heard this word repeated many times, and often
wondered exactly what it means. This is an attempt to explain it.

Dictionary Definition

The Concise Oxford English Dictionary's
definition is too long to copy down here¹,
but the gist of it is that it is used for comparisons and to confer
certain properties onto an object (eg. 'That painting is like this one.', and
'It's just like driving.'), and expressing affinity, affection or another
similar concept (eg. I like dogs). The comparison category includes simile,
as taught in English/other language classes.

Modern (Ab)Usage

As witnessed in such fine documentary films as Clueless, and most
anything else that has come out of Hollywood in the past few years, as well as
in almost any locality in the USA, the word 'like' has taken on more meanings
than the word 'well'. One might even go so far
as to say that its usage causes it to defy definition. Nevertheless, an
attempt will be made to define it anyway. 'Like' is used:

1. As an 'um' or 'er' word. (eg. 'It was, like, really cool.', or 'How
   can I fail English? I'm, like, fluent.')

2. To express a thought or feeling while relating a situation to others.
   This is expressed in either the present or past tense, even though the event
   has already occurred. (eg. 'And I was like: "Get away from me you freak!"')
   

3. To express something said while relating a situation to others. See
   note above for tense information. (eg. 'And I was like: "Get away from me you
   freak!"' (Yes, it's the same quote as above.))

4. To express something which the speaker feels that the listener ought to
   know telepathically. This is often, but not always, used in conjunction with
   the either the question 'you know?', or the question 'y'know?'. (eg. 'It was,
   like, y'know?')

5. To partially confer the qualities of a, possibly strong, adjective onto
   the subject. In this usage it mirrors one of the actual dictionary uses, but
   is very easily confused with its usage in definition 1. (eg. 'He was, like,
   insane.')

6. To express anything else.

As can be seen above, especially from definitions 2 and 3, the usage of the
word is highly confusing, and comprehension depends largely on an
understanding of context and one's psychic ability. Mostly, the confusion
arises from the incredibly fuzzy way in which the word is used, much as the
verb 'to go' used to be used for movement, speech, and so on.

As near as can be discovered, this alarming trend started in Beverly Hills
among rich teens, has since spread across the USA, and seems as if it is now
coming to plague the UK. Hollywood has not helped this situation by producing
films and television shows aimed at teenagers, replete with 'realistic' teen
dialog. Some language researchers believe that this trend has come about
because people, especially teenagers, are afraid to express any thought
concretely, and that adding a fuzzy word such as 'like' softens this. The
author of this entry believes that it is nothing more than a bad habit that no
one wants to go out of his/her way to break, or to even realize that it
exists.