How "uh" and "um" differ

If you’ve been following the recent discussions on Language Log, then you know that there is a great deal of inter-speaker variation in the use of the fillers uh and um, despite their superficial similarity. In this post, I’ll discuss some published results, summarize some of the Language Log findings (with the obvious caveat that none of it has been subject to any sort of peer review) and explain what I think it all means for our understanding of the contrast between uh and um.

The function of uh and um

The vast majority of work on disfluencies (which include fillers like uh and um as well as repetitions, revisions, and false starts) assumes that uh and um are functionally equivalent, substitutable forms. But Clark and Fox Tree (2002) argue that they are subtly different. They claim that uh serves as signal minor delays and um signals major delays. The evidence for this is straightforward:

  • Um is more often followed by a pause than uh.
  • Pauses after ums tend to be longer than those occurring after uhs (though Mark has failed to replicate this in a much larger corpus, and I am inclined to defer to him).
  • Um is more common than uh in utterance-initial position, the point at which speech planning demands are presumably at their greatest. [1]

From these results, though, it is not obvious that uh and um are qualitatively different. This has not prevented people (myself included) from making this jump. For example, Mark speculated a bit about this for the Atlantic: “People tend to use UM when they’re trying to decide what to say, and UH when they’re trying to decide how to say it.” This is plausible, but the evidence for differential functions of uh and um is lacking.

Intraspeaker differences in uh and um

Gender effects

The first—and probably most robust—finding, is that female speakers have a higher average um/uh ratio than males. This pattern was found in several corpora of American English available from the LDC (1 2 3). It also reported in a recent paper by Acton (2011), who looks two American English corpora. A higher um/uh ratio in females was also found in two corpora of British English. The first looks at data from the HCRC map task and the second at the conversational portion of the British National Corpus (BNC). The latter was earlier the subject of a study by Rayson et al. (1997), who found that that er (the British equivalent of uh) [2] was the one of the words most strongly associated with male (rather than female) speakers; the only word more “masculine” than uh was the expletive fucking.

Social class effects

The second finding is that um/uh ratio is correlated with social class: higher status speakers have a higher um/uh ratio. Once again, this was first reported by Rayson et al., who found that erm is more common in speakers with high-status occupations. Mark found a similar pattern in American English using educational attainment—rather than occupation—as a measure of social class.

Age effects

The third finding is that younger speakers have a higher um/uh ratio than older speakers. This was first reported by Rayson et al. (once again, studying the conversational portion of the BNC), who found that that er is much more common in speakers over the age of 35. Similar patterns are reported by Acton, and several Language Log correspondents (1 2 3 4).

Geographic effects

Finally, Jack Grieve looked at um/uh ratio geographically, and found that um was more common in the Midlands and the central southwest. I see two issues with this result, however. First, I don’t observe any geographic patterns in the raw data (ibid., in the comments section of that post); to my eye, the geographic patterns only emerge after aggressive smoothing; this may just be another case of Smoothers Gone Wild. Secondly, the data was taken from geocoded Twitter posts, not speech. As commenter “BK” asks: “do we have any reason to believe that writing ‘UM’ vs ‘UH’ in a tweet is at all correlated with the use of ‘UM’ vs ‘UH’ in speech?” Regrettably, I suspect the answer is no, but there still is probably something to be gleaned from tweeters’ stylistic use of these fillers.

Uh and um in children with autism

Our recent work on filler use in children with autism spectrum disorders (ASD) might provide us another way to get at the functional differentiation between uh and um. We [3] used a semi-structured corpus of diagnostic interviews of children ages 4-8, and find that children with ASD produce a much lower umuh ratio than typically developing children matched for age and intelligence. Children with specific language impairment—a neurodevelopmental disorder characterized by language delays or deficits in the absence of other developmental or sensory impairments—have an umuh ratio much closer to the typical children; this tells us it’s not about language impairment (something which is relatively common—but not specific to—children with ASD). We also find that umuh ratio is correlated with the Communication Total Score of the Social Communication Questionnaire, a parent-reported measure of communication ability. At the very least, individuals who use more um are perceived to have better communication abilities by their parents. At best, use of um itself contributes to these perceptions.

How uh and um differ

To the sociolinguistic eye, the effects of gender, class, and age just described tell us a lot about uh and um. Given that women have a higher um/uh ratio than men, we expect that um is either the more prestigious variant, or the incoming variant, or both. This is what Labov calls the gender paradox: women consistently lead men in the use of prestige variants, and lead men in the adoption of innovative variants. Further evidence that um is the prestige variant comes from social class: higher status individuals have a higher um/uh ratio. Younger speakers have a higher um/uh ratio, suggesting that um is also the incoming variant. This is not the only possible interpretation, however; it may be that the variants are subject to age grading—meaning that speakers change their use of uh and um as they age—which does not entail that there is any change in progress. Given a change in apparent time—meaning that younger and older speakers use the variants at different rates—the only way to tell whether there is change in progress is to look at data collected at multiple time points. While the evidence is limited, it looks like both age grading and change in progress are occurring—they are not mutually exclusive, after all.

Unfortunately, some evidence from style shifting problematizes this view of um as a prestige variant. O’Connell and Kowal (2005) look at uh and um by analyzing the speech of professional TV and radio personalities interviewing Hillary Clinton. If um is the more prestigious variant, then we would expect a higher um/uh ratio in this formal context compared to the more casual styles recorded in other corpora. But in fact these experienced public speakers have a particularly low um/uh ratio. Hillary Clinton produced 640 uhs and 160 ums, for an um/uh ratio of 0.250; in contrast, Mark found that on average, female speakers in the Fisher corpora favored um more than 2-to-1.

So why is Hillary Clinton hating on um? Can an incoming variable be associated with women and the upper classes yet still avoided in formal contexts? Or are we simply wrong to think of uh and um as variants of a single variable? Is it possible that, given our limited understanding of the functional differences between uh and um, we have failed to account for associations between discourse demands and social groups (or speech styles)? Perhaps Clinton just needs uh more than we could ever know.


[1] This finding is so robust, it even holds in Dutch, which has very similar fillers to those of English (Swerts 1998).
[2] Note that, at least according to the Oxford English Dictionary, British er and erm are just orthographic variants of uh and um, respectively. That’s not to say that they’re pronounced identically, just that they are functionally equivalent.
[3] Early studies geared at speech researchers were conducted by Peter Heeman and Rebecca Lunsford. Other coauthors include Lindsay Olson, Alison Presmanes Hill, and Jan van Santen.


E.K. Acton. 2011. On gender differences in the distribution of um and uhPenn Working Papers in Linguistics 17(2): 1-9.
H.H. Clark & J.E. Fox Tree. 2002. Using uh and um in spontaneous speaking. Cognition 84(1): 73-111.
D.C. O’Connell and S. Kowal. 2005. Uh and um revisited: Are they interjections for signaling delay? Journal of Psycholinguistic Research 34(6): 555-576.
P. Rayson, G. Leech, and M. Hodges. 1997. Social differentiation in the use of English vocabulary: Some analyses of the conversational component of the British National Corpus. International Journal of Corpus Linguistics 2(1): 133-152.
M. Swerts. 1998. Filled pauses as markers of discourse structure. Journal of Pragmatics 30(4): 485-496.

(ing): now with 100% more enregisterment!

In his new novel Bleeding Edge, Thomas Pynchon employs a curious bit of eye dialect for Vyrna McElmo, one of the denizen of his bizarro pre-9/11 NYC:

All day down there. I’m still, like, vibrateen? He’s a bundle of energy, that guy.

Oh? Torn? You’ll think it’s just hippyeen around, but I’m not that cool with a whole shitload of money crashing into our life right now?

What’s going on with vibrateen and hippyeen? I can’t be sure what Pynchon has in mind here—who can? But I speculate the ever-observant author is transcribing a very subtle bit of dialectical variation which has managed to escape the notice of most linguists. But first, a bit of background.

In English, words ending in <ng>, like sing or bang, are not usually pronounced with final [g] as the orthography might lead you to believe. Rather, they end with a single nasal consonant, either dorsal [ŋ] or coronal [n]. This subtle point of English pronunciation is not something most speakers are consciously aware of. But [n ~ ŋ] variation is sometimes commented on in popular discourse, albeit in a phonetically imprecise fashion: the coronal [n] variant is stigmatized as “g-dropping” (once again, despite the fact that neither variant actually contains a [g]). Everyone uses both variants to some degree. But the “dropped” [n] variant can be fraught: Peggy Noonan says it’s inauthentic, Samuel L. Jackson says it’s a sign of mediocrity, and merely transcribing it (as in “good mornin’“) might even get you accused of racism.

Pynchon presumably intends his -eens to be pronounced [in] on analogy with keen and seen. As it happens, [in] is a rarely-discussed variant of <ing> found in the speech of many younger Midwesterners and West Coast types, including yours truly. [1] Vyrna, of course, is a recent transplant from Silicon Valley and her dialogue contains other California features, including intensifiers awesome and totally and discourse particle like. And, I presume that Pynchon is attempting to transcribe high rising terminals, AKA uptalk—another feature associated with the West Coast—when he puts question marks on her declarative sentences (as in the passages above).

Only a tiny fraction of everyday linguistic variation is ever subject to social evaluation, and even less comes to be associated with groups of speakers, attitudes, or regions. As far as I know, this is the first time this variant has received any sort of popular discussion. -een may be on its way to becoming a California dialect marker (to use William Labov’s term [2]), though in reality it has a much wider geographic range.


[1] This does not exhaust the space of (ing) variant, of course. One of the two ancestors of modern (ing) is the Old English deverbal nominalization suffix -ing [iŋg]. In Principles of the English Language (1756), James Elphinston writes that [ŋg] had not fully coalesced, and that the [iŋg] variant was found in careful speech or “upon solemn occasions”. Today this variant is a stereotype of Scouse, and with [ɪŋk], occurs in some contact-induced lects.
[2] It is customary to also refer to Michael Silverstein for his notion of indexical order. Unfortunately, I still do not understand what Silverstein’s impenetrable prose adds to the discussion, but feel free to comment if you think you can explain it to me.

On the Providence word gap intervention

A recent piece in the Boston Globe quoted my take on a grant to Providence, RI for a “word-gap” intervention. In this quote, I expressed some skepticism about the grant’s goals, but omitted the part of the email where I explained why I felt that way. Readers of the piece might have gotten the impression that I had a less, uhm, nuanced take on the Providence grant than I do. So, here is a summary of my full email to Ben from which the quote was taken.

An ambitious proposal

First off, the Providence/LENA team should be congratulated on this successful grant application: I’m glad they got it and not something more “Bloombergian” (like, say, an experimental proposal to ban free-pizzas-with-beer deals in the interest of bulging hipster waistlines). And they deserve respect for getting approved for such an ambitious proposal: the cash involved is an order of magnitude larger than the average applied linguistics grants. And, perhaps most of all, I have a great deal of respect for any linguist who can convince a group of non-experts that, not only is their work important, but that it is worth the opportunity cost. I also note that if materials from the Providence study are made publicly available (and they should be, in a suitably de-identified format, for the sake of the progress of the human race), my own research stands to benefit from this grant.

But there is another sense in which the proposal is ambitious, however: the success of this intervention depends on a long chain of inferences. If any one of these is wrong, the intervention is unlikely to succeed. Here are what I see as the major assumptions under which the intervention is being funded.

Assumption I: There exists a “word gap” in lower-income children

I was initially skeptical of this claim because it is so similar to a discredited assumption of 20th century educational theorists: the assumption that differences in school and standardized test performance were the result of the “linguistically impoverished” environment in which lower class (and especially minority) speakers grew up.

This strikes me as quite silly: no one who has even a tenuous acquintance with African-American communities could fail to note the importance of verbal skills in said community. Every African-American stereotype I can think of has one thing in common: an emphasis on verbal abilities. Here’s what Bill Labov, founder of sociolinguistics, had to say in his 1972 book, Language in the Inner City:

Black children from the ghetto area are said to receive little verbal stimulation, to hear very little well-formed language, and as a result are impoverished in their means of verbal expression…Unfortunately, these notions are based upon the work of educational psychologists who know very little about language and even less about black children. The concept of verbal deprivation has no basis in social reality. In fact, black children in the urban ghettos receive a great deal of verbal stimulation…and participate fully in a highly verbal culture. (p. 201)

I suspect that Labov may have dismissed the possibility of input deficits prematurely, just as I did. After all, it is an empirical hypothesis, and while Betty Hart and Todd Risley’s original study on differences in lexical input involved a small and perhaps-atypical sample, but the correlation between socioeconomic status and lexical input has been many times replicated. So, there may be something to the “impoverishment theory” after all.

Assumption II: LENA can really estimate input frequency

Can we really count words using current speech technology? In a recent Language Log post, Mark Liberman speculated that counting words might be beyond the state of the art. While I have been unable to find much information on the researchers behind the grant or behind LENA, I don’t see any reason to doubt that the LENA Foundation has in fact built a useful state-of-the-art speech system that allows them to estimate input frequencies with great precision. One thing that gives me hope is that a technical report by LENA researchers provides estimates average input frequency in English which are quite close to an estimate computed by developmentalist Dan Swingley (in a peer-reviewed journal) using entirely different methods.

Assumption III: The “word gap” can be solved by intervention

For children who are identified as “at risk”, the Providence intervention offers the following:

Families participating in Providence Talks would receive these data during a monthly coaching visit along with targeted coaching and information on existing community resources like read-aloud programs at neighborhood libraries or special events at local children’s museums.

Will this have an long-term effect? I simply don’t know of any work looking into this (though please comment if you’re aware of something relevant), so this too is a strong assumption.

Given that there is now money in the budget for coaching, why are LENA devices necessary? Would it be better if any concerned parent could get coaching?

And, finally, do the caretakers of the most at-risk children really have time to give to this intervention? I believe the most obvious explanation of the correlation between verbal input and socioeconomic status is that caretakers on the lower end of the socioeconomic scale have less time to give to their children’s education: this follows from the observation that child care quality is a strong predictor of cognitive abilities. If this is the case, then simply offering counseling will do little to eliminate the word gap, since the families most at risk are the least able to take advantage of the intervention.

Assumption IV: The “word gap” has serious life consequences

Lexical input is clearly important for language development: it is, in some sense, the sole factor determining whether a typically developing child acquires English or Yawelmani. And, we know the devastating consequences of impoverished lexical input.

But here we are at risk of falling for the all-too-common fallacy which equates predictors of variance within clinical and subclinical populations. While massively impoverished language input gives rise to clinical language deficits, it does not follow that differences in language skills within typically developing children can be eliminated by leveling the language input playing field.

Word knowledge (as measured by verbal IQ, for instance) is correlated with many other measures of language attainment, but are increases in language skills enough to help an at-risk child to escape the ghetto (so to speak)?

This is the most ambitious assumption of the Providence intervention. Because there is such a strong correlation between lexical input and social class, it is very difficult to control for this while manipuating lexical input (and doing so would presumably be wildly unethical), we know very little on this subject. I hope that the Providence study will shed some light on this question.

So what’s wrong with more words?

This is exactly what my mom wanted to know when I sent her a link to the Globe piece. She wanted to emphasize that I only got the highest-quality word-frequency distributions all throughout my critical period! I support, tentatively, the Providence initiative and wish them the best of luck; if these assumptions all turn out to be true, the organizers and scientists behind the grant will be real heroes to me.

But, that leads me to the only negative effect this intervention could have: if closing the word gap does little to influence long-term educational outcomes, it will have made concerned parents unduly anxious about the environment they provide for their children. And that just ain’t right.

(Disclaimer: I work for OHSU, where I’m supported by grants, but these are my professional and personal opinions, not those of my employer or funding agencies. That should be obvious, but you never know.)