35

Many times I heard these words interchangeably. I want to know if "Let's" and "Let us" are used for the same meaning.

I think (for me):

  • "Let us" is word used for requesting. Like Let us do something means requesting to allow us do something.
  • "Let's" is words used for proposing. Like Let's play means proposing people to play.
  • 1
  • 2
    @FumbleFingers A very good point. In American use it's reduced phonologically, too: "Less go!", or even "Sko!". – StoneyB Aug 20 '15 at 16:14
  • 1
    @StoneyB: Ditto BrE. Real speech can be very "reduced", and it's also perfectly natural in BrE (not so sure about AmE) for us to be used in certain contexts to mean me. So, for example, Let me see (both as Give me a moment to think and Let me have a look) can actually be enunciated as no more than [schwa/glottal stop] see in relaxed conversational contexts. – FumbleFingers Aug 20 '15 at 16:55
  • @StoneyB it's now been shortened further, to leggo - youtube.com/watch?v=m9PXLjulGio – Kik Aug 20 '15 at 17:42
  • 1
    I think the key point (in British English), which is implied but not explicitly stated in several of the answers, is that "Let's X" is used in situations where the action X will involve the speaker and other people doing something, but "Let us X" is a request for a different person or persons to perform some action which gives permission, or makes it physically possible, for the speaker and his/her companions to do X. Replacing this usage of "Let's" with "Let us" is only idiomatic in formal speech or writing, for example. "Let us first consider the case where ...." in a formal report. – alephzero Aug 20 '15 at 20:35
44

Yes, let's is indeed simply a contraction of let us, and that means that whenever you can use let's, you can use let us.

But that is not the whole story!

The expression let's (or let us when used in the same way) is idiomatic; it means something different than you would think by just looking at the dictionary definition of let.

You correctly mentioned that let's play is a proposal or encouragement to play something.

Now, the normal meaning of let is different, as you noticed as well. It means "to allow or enable something". When you say let us into the house, you are using the imperative. That means you are giving someone an order.

Let us into the house means make it possible for us to move into the house.

It is important to understand that you do not use the contraction let's in this situation! *Let's into the house is not correct.

Now, in some cases, a sentence may be read in two different ways, and that can be confusing. Look at the two sentences:

Let's go in.
Let us go in.

They can both mean "I propose that we go in", but the second one can also mean "Allow us to go inside!"
The actual meaning of the second sentence depends on context:

It's getting cold outside, let us (let's) go in!
We need to search your house. Let us in!

  • 5
    I hate to make this more difficult or nuanced than necessary, but let's is also an imperative, if a weak one. The English Let's go! is pretty much the same as the French Allons! It's weak because the speaker is part of the group rather than apart from it; the authority depends on the speaker's position within the group. – Stan Rogers Aug 20 '15 at 12:43
  • @StanRogers Yes, let's is also an imperative. But since its use is basically completely idiomatic, I don't think we need to analyse much further than its actual meaning in everyday use. Would this have been a question on ELU, the answer would probably have been much more detailed :) – oerkelens Aug 20 '15 at 13:29
  • 3
    I think it's worth noting that except in certain stylized contexts, replacing "let's" with "let us" will almost never sound natural to a native speaker in anything even close to a colloquial (non-formal) setting (at least in the US). If you said to a friend, "hey, let us go watch a movie tonight," that will not sound "right" to them; it will sound archaic and out of place. – yshavit Aug 21 '15 at 20:45
  • 1
    @yshavit - Spot on. One example where it's almost the other way around is let us pray. – J.R. Aug 21 '15 at 20:50
  • 1
    @J.R. Yes, good example! I think that's actually consistent with what I wrote (and I just mention that so that the OP doesn't read this and think "exceptions to exceptions, this is too complex!"). Let us pray is spoken in a religious context, and ties the speaker back to the history of their religion. In other words it's purposefully archaic-sounding. If "let's pray" is a plain proposal to pray, then "let us pray" has a hint of "... as our ancestors did," since the archaic form sounds like something those ancestors might have said. – yshavit Aug 21 '15 at 21:04
12

You understand the forms in colloquial use pretty much correctly.

  • Let's VERB is used to propose or encourage the action of VERB by the speaker and her hearers. Let here is a (now mostly obsolete) subjunctive use of the plain form.

    It's getting late. Let's go!

  • Let us VERB is ordinarily used to request or demand permission for the speaker and her associates to perform the action of VERB. Let here is an imperative use of the plain form.

    Please let us go to the party.

  • The same form is also used as an indicative in both present and past tense: the past and present forms are identical, except that the usual -s suffix is used with the 3d person singular in the present tense.

    Dad letspresent us go to the pool when we have finished our homework.
    Dad letpast us go to the pool when we had finished our homework.

However, let's is a contraction of let us; so in more formal contexts let us may have the same sense as let's:

Let us now praise famous men is a quotation from the Bible, employed as the title of a well-known book by writer James Agee and photographer Walker Evans.

Let us pray is an invitation to prayer frequently heard in church.

  • Please let us go to the party is an interesting one. In the context of a brother and sister asking for parental permission, it is as you say. But in the context of a husband and wife getting ready to go out together – It's getting late, please let us go to the party – it means something a little different (i.e., "let's get going), and it would almost always be said as "let's," not "let us." – J.R. Aug 23 '15 at 1:06
0

Let’s is the English cohortative word, meaning “let us” in an exhortation of the group including the speaker to do something.

Lets is the third person singular present tense form of the verb let meaning to permit or allow.

In the questioner’s examples, the sentence means to say “Product (allows/permits you to) do something awesome”, so the form with lets is correct.

  • 2
    But the question doesn't mention "lets" at all. It does, however, ask about "let us", which is both an exhortation ("let us pray") and a demand for permission ("Let us in!"). – David Richerby Aug 21 '15 at 8:24
-1

You are correct. Here is another example:

We have been kidnapped; let us go.

We have been kidnapped; let's go.

These do not have quite the same meaning. In the first, the kidnapped people are asking their kidnappers to let them go. In the second, the kidnapped people are talking among themselves, planning an escape.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.