(A few videos are included in this page.)

dendrobates azureus
"blue tree-walker"
Compounding is a morphological  process, a word formation process. Compound words are formed with two or more base words, as in songbird and polar ice cap. They are also formed with roots or bases -- usually Latin or Greek bases, as in manuscript and telescope. Many scientific terms are compound words composed of several bases, including über-lengthy chemical names and more succinct animal classification taxonomies. For example, the picture shows a poisonous frog. Its scientific name, dendrobates azureus, is a compound that means 'blue tree-walker.'  Another example of a scientific compound word is Homo Erectus, a genus and species combination that means 'man' (homo) and 'upright' (erectus), or 'upright man,' which is not the same as Homo Sapiens, 'men' who are 'wise, sapient, perceiving' -- women and children, too.

bottlenose dolphin
Latin and Greek aside, common English base words are frequently combined to form compounds. Noun-noun compounds are common, such as doghouse, breadbox, rainbow. Many compounds use hyphenated base words as modifiers: red-headed woodpecker, ruby-throated hummingbird, long-tailed brush lizard. To demonstrate that they understand how these more complicated compounds convey meaning, second or third grade students should be able to restate them, somewhat like this: "A red-tailed hawk is a hawk with a red mark on its tail" or "A bottlenose dolphin is a dolphin with a nose that looks a little like a bottle." This may be difficult for some.

What qualifies a phrase to be conceptualized as a compound? Dictionaries sometimes offer conflicting reports; here's a useful rule of thumb: Typically, in common usage, no other word is inserted inside a compound, breaking it up. Examples: We tend not to say, "My ice cold cubes have melted," or "A polar big bear is dangerous."  Likewise, we say "sandbox" but not "sand and shovel box" or "sand circle" (not even in the case of a round sandbox).

Three ways to structure a compound: The base words that make up a compound may be connected (called closed compounds, as in sunshine, baseball, flashlight), hyphenated (self-esteem, son-in-law, jack-in-the-box) or the words may stand apart. These are called open compounds, as in ice cube, book jacket, swing set. Some compounds are closed. Others are open. Still others are hyphenated. Why is this? Michael Quinion provides insight. The following text is quoted from his website, World Wide Words:
Compound nouns have traditionally begun as separate or hyphenated words but with a strong tendency over time to collapse into single words. A century ago, it was standard practice to write to-day, but the hyphen has long since evaporated from the page; similarly with teenager (teen-ager from its first use in 1941 until the later 1950s) and lipstick (it was two words in the 1880s, but became hyphenated around the 1920s). Americans have long been much more willing to write words such as postmodern without the hyphens that British standards require. (from Hyphen page)


A MORE important issue yet remains, one that is concerned with learning word meanings: In many (but not all) compound words, the final word carries most of the linguistic load. In that case, the final, right-most word is the head of the compound. For example, in the case of treehouse the head is house. The head describes the basic meaning of the word, indicating the semantic category (a kind of house) and also the grammatical word class (a noun). The modifier elaborates (tree modifies house). Help students understand this principle: Help them see that the final word in many compound words indicates the category. Thus:
  • A doghouse is a kind of house but a house dog is a kind of dog.
  • A sandstorm is a kind of storm but a storm cloud is a kind of cloud. 
  • A sandbox is a kind of box but quicksand is a kind of sand.

Understanding any given compound will also require context, else one could think a goldfish is a fish made of metal rather than muscle (or grain).

There are also compound words that cannot be interpreted by looking at the final word (headless compounds). Examples: A pickpocket is not a type of pocket, a bulldozer does not doze, and a lazy Susan does not describe a person (not usually). Without internal word clues as to the meaning, we must hope for external and explicit context clues or we must refer to a dictionary.

Compounds are plentiful in the English language. My own research (Ebbers, 2008) revealed that compounds were the most common type of word family in the second-grade science and reading texts I sampled. We cannot assume that school-age children intuitively understand how compounds convey meaning. Building on prior research, Nagy, Berninger, Abbott, Vaughan, and Vermeulen (2003) found that many of the 195 at-risk readers and writers they tested did not intuitively understand noun-noun compounds (barnyard is a noun-noun compound, for example). When shown a picture of bees in the grass and asked to decide between two options, the second graders were as apt to name the pictured grass "grass bee" as they were to call it "bee grass" (the test also included the opposite question: "Which is a better name for the bees who live in the grass?"). There were 14 questions of this nature. At-risk second graders correctly responded to 52% of the items and at-risk fourth graders correctly responded to 72% of the items. It seems that over two years there is developmental growth in understanding compound word structure, but time alone is not likely to sufficiently address the confusion. 

Recently, related research showed that Chinese-speaking students in 5th grade benefited from learning how English compounds work in comparison to Chinese compounds (Zhang et al., 2010). Through instruction, the intervention group made significant gains beyond the control group in understanding both English and Chinese compound words.

Whether our students are English language learners, at-risk readers, or just a little confused, a little instruction might go a long way. After teaching how compound words are structured to convey meaning, provide opportunities to apply the concept when speaking, listening, reading and writing. 

For example, a teacher might help children create a compounding flip-book. The basic idea is shown in the morpheme flip-book video below, created by Margaret Campbell. For basic compounds, the students only need two columns. Or see video at YouTube. 


For primary grades, a two-column flip-book might include compounds ending in house for example: lighthouse, boathouse, birdhouse, bathhouse, farm house, playhouse, tree house, greenhouse, dollhouse, doghouse, firehouse, funhouse, publishing house, schoolhouse, White House, etc. Let the children invent some! Have them describe their neologisms to one another: "A bookhouse is a house full of books!" ("No, a bookhouse is a house made of books!")

Most reading programs call for children to merely divide compounds into constituent parts. In addition to that type of decoding activity, children should also work on meaning. They should be able to roughly explain any endocentric compound, even invented words, somewhat like this: A mintberry is a berry that ... smells like mint? tastes like mint? is mint green? The key's a kind of berry, not a kind of mint. Furthermore, students should be able to differentiate between compounds whose meaning can be "figured out" somewhat by looking at the constituent parts, and those that cannot. To see if they can do so, ask them questions, like "Which one is more truly a kind of box, a shoe box, a voice box or an Xbox?" Discuss how these items do and/or do not reflect the concept of 'box' and encourage critical thinking rather than a right-wrong mindset.

For more details, see the video below.  Jurgen Handke (2012) describes the technical properties of compounds, including the grammatical head of the word and the difference between endocentric and exocentric compounds. This is one of a series published by Virtual Linguistics Campus. If the video doesn't play here, go directly to YouTube.

There is a series of morphology videos created by student-linguists at Marlburg University. Sadly, the compounding video I had posted here disappeared, but I leave the thought behind. Must be out there somewhere.


Ebbers, S.M. (2008).  Morphological word families in narrative and informational text.  In Y. Kim, V.J. Risko, D. L. Compton,  D.K. Dickinson, M. K. Hundley,  R. T. Jimenez, et al. (Eds.), 57th Yearbook of the National Reading Conference ( pp. 203-218). Oak Creek, WI:  NRC.

Nagy, W.E., Berninger, V., Abbott, R., Vaughan, K., & Vermeulen, K. (2003). Relationship of morphology and other language skills to literacy skills in at-risk second grade readers and at-risk fourth grade writers. Journal of Educational Psychology, 95, 730-742. 

Zhang, J., Anderson, R. C., Li, H., Dong, Q., Wu, X., & Zhang, Y. (2010). Cross-language transfer of insight into the structure of compound words. Reading and Writing, 23(3-4), 311-336.