I have seen/heard constructions similar to "people ages 20 to 30" many times. However, several discussions, including questions on ELU, suggest the aforementioned construction is ungrammatical/typo: see here, here, here, and here (of course there was some debate over this issue). These questions all seem inconclusive and undetermined. It's intriguing how on the one hand there's a plethora of attestations of this usage all over the Internet and on the other you have people one after another saying it is ungrammatical and/or a typo, not without comments to the contrary.
Examples include:
There, every day, dozens of children ages 3 to 5 come to have adventures on Irvine’s more than 200 acres of woodlands, wetlands, and meadows. (The Atlantic)
Teen suicide is a growing health concern. It is the third-leading cause of death for young people ages 15 to 24, surpassed only by homicide and accidents, according to the U.S. Center for Disease Control and Prevention. (APA)
In 2012, 87.6 percent of people ages 18 or older reported that they drank alcohol at some point in their lifetime. (NIAAA)
So can we definitely determine this construction is ungrammatical? If that's not the case, then how do we parse these sentences? I am having the same issue a lot of people apparently had/have. While aged 15 to 24 is a participial phrase, what kind of phrase is ages 15 to 24 and how does it modify the preceding noun? A parse tree would be very helpful.
Best Answer
[1] a. It is the third-leading cause of death for young people ages 15 to 24.
b. While parents are off shopping, children ages 3 to 8 can play in the
glass-enclosed child-care center.
c. Nearly one-third of the people ages 15 to 34, and more than half of
those ages 35 to 44 had hypertension.
1. Acceptability. It is true that some native speakers do not find constructions such as those in [1] acceptable (this is evident from the discussions on this website). (EDIT: as documented in Araucaria's answer on this page, this seems to be an AmE vs BrE split, with the construction being very standard in American English, but far less universally acceptable in British English.) Nevertheless, on the whole, balance of evidence shows that this type of construction is nowadays part of Standard English at least in the context of news and in scientific/medical literature. (And at least in American English.) Below, I will present several representative pieces of evidence for this, one of which is an explicit endorsement of this construction from a style manual (Urban Institue Editorial Style Guide).
2. Syntactical analysis. It is uncontroversial that if the sentences in [1] are acceptable, then the boldfaced parts are noun phrases (NPs). It is also uncontroversial that (if the sentences in [1] are acceptable, then) the constructions ages 15 to 24 etc. are themselves NPs, functioning as some sort of dependent in the larger, matrix NP.
I have been unable to find a treatment of this particular construction in the literature. But, for what it's worth, it seems to me that there are at least two ways to analyze the function of these 'internal' NPs within their matrix NPs:
(a) NP as a post-head modifier in a matrix NP. True, NPs are rare in this function, but not unheard of. Examples include expressions such as (CGEL, p. 446)
[2] a man my age shoes this size
the results last year houses this side of the lake
As CGEL says about these examples, 'modifiers with NP form are limited to those denoting age, size, and similar properties' (emphasis mine).
(b) NP as a complement of the preposition of, where we have an ellipsis of the preposition. On this account, people ages 15 to 24 is really people of ages 15 to 24, where the preposition of has been ellipted. In the non-ellipted version, ages 15 to 24 is a complement of of, and the whole preposition phrase (PP) of ages 15 to 24 is a post-head modifier of people, which is the head of the matrix NP. In its discussion of post-head modifiers, CGEL says that (p. 445, emphasis mine)
Of course, one could similarly say that the examples in [2] are all cases of preposition ellipsis (a man of my age, shoes of this size, the results from last year, houses on this side of the lake). Note, however, that CGEL does not do this. They don't explain why. All I can tell you is what I think, and it is this: to a linguist, an ellipsis is always a last resort, something one postulates to explain how a construction that doesn't seem to fit into the larger system of syntax could nevertheless fit into that system. But there is no reason why English should absolutely disallow NPs as post-head modifiers in a matrix NP; certainly there are other languages that allow them (and without any invocation of an ellipsis). Thus, we might as well say that such constructions are allowed, if rare. Other than this principle ('ellipsis is a last resort'), I do not know how to decide whether (a) or (b) should be preferred.
Evidence of acceptability
Garner's Modern American Usage uses the following example in its discussion of enclose/inclose on p. 297 (emphasis mine):
The Merriam-Webster Dictionary gives the following sentence as an example of usage in its entry for age (here). The sentence is taken from an article in a major daily newspaper:
The Urban Institue Editorial Style Guide (here) gives the following recommendations for 'age':
This construction is not restricted to plurals:
In Clinical Handbook of Psychotropic Drugs for Children and Adolescents: 3rd ed we find
And in Straight A's in Pediatric Nursing, we have numerous instances of constructions such as
All of the above is just the tip of the iceberg. This type of construction is simply super-well attested in edited scholarly and journalistic publications, written by well-educated native speakers.
Let me close with just one final example: the journal article 'The Processing and Interpretation of Verb Phrase Ellipsis Constructions by Children at Normal and Slowed Speech Rates' by Sarah M. Callahan, Matthew Walenski, and Tracy Love (J. Speech Lang. Hear. Res. 55, 710-725, 2012; full text available here):