Question from English4Today member Ellen in China:

 Apart from the “cue” word, ‘fall’, which comes before asleep, can you kindly tell me when to use asleep and when to use sleep?

Hello Ellen. Thanks for your question. Well, the most important difference between ‘sleep’ and ‘asleep’ grammatically is that ‘sleep’ is either a verb or a noun while ‘asleep’ is either an adverb or an adjective. What this means, in terms of how we use them is that different grammatical rules are going to apply depending on whether we are using a noun, verb, adjective or adverb.

Let’s look at ‘sleep’ as a noun first:

  • Did you have a good sleep?
  • Her sleep was troubled by nightmares.
  • The Big Sleep

The Big Sleep‘ was, of course, the title of a Raymond Chandler novel and the classic movie adaption of it starring Humphrey Bogart and Lauren Bacall.

That’s fairly easy to see, I think.

Sleep as a Noun

Now let’s look at ‘to sleep’ the verb:

  • She slept until late afternoon.
  • May has not been sleeping well.
  • Is Dimitri sleeping? I don’t want to wake him.

I think that too is pretty clear as the use of the irregular verb ‘to sleep’ in tenses is very standard – other than the fact that it is an irregular verb (sleep, slept, slept).

So, how about ‘asleep’? Here are example of asleep used as an adjective or an adverb:

Asleep =  adverb

  • Georgia fell asleep as soon as she went to bed.
  • Paddy and Molly fell asleep on the train and missed their station.

You’ll see ‘asleep’ as an adverb most commonly with the verb ‘to fall’  and as an adjective with the verb ‘to be’ – and as you say, Ellen, these are cue words that you can use to recognize the adverbial or adjectival use of ‘asleep’. If I re-write the above sentences using ‘to sleep’ they would look like this:

  • Georgia slept as soon as she went to bed.
  • Paddy and Molly slept on the train and missed their station.

Notice that when we use ‘to fall’ + ‘asleep’ there is always a sense of the action happening suddenly which we can’t get just by using the verb ‘to sleep’ by itself.

Now let’s look at ‘asleep’ as an adjective:

Asleep = adjective

  • My foot is asleep (meaning I cannot feel it).
  • The dog is asleep – I wouldn’t wake him if I were you!
  • Dax was asleep when you called

Note: it is not possible to use ‘to sleep’ in the passive form.

Hope that has cleared that up a little Ellen and that my explanation has put you to sleep!