23. Pronunciation of compound words in English

You may be disappointed by this SECTION because there are no definitive answers.

Start with the words dragonfly and butterfly. They are compound words formed from simple English words. A dot is used in the following text to show where the break between the parts of the compound occurs: dragon.fly and butter.fly. Bold letters are used in the following text to show the location of the stress when the word is pronounced: dragon.fly, butter.fly, arrow.head and thunder.cloud. The rule seems to be that we place the stress on one of the syllables of the root word. But, when we try to apply this "rule" to compound words in science, it breaks down. Column A below applies "the rule" and column B shows something else.


 al.chemy  alchemy
 chemi.stry  chemistry
 al.gebra  algebra
 alti.tude  altitude
 alti.meter  altimeter
 centi.meter  centimeter
 cumulo.nimbus  cumulonimbus
 milli.meter  millimeter
 geo.metry  geometry
 geo.thermal  geothermal
 kilo.meter  kilometer
 kilo.gram  kilogram
 poly.syllable  polysyllable
 thermo.meter  thermometer
 testo.sterone  testosterone
 tele.phone  telephone
 tele.scope  telescope
 tele.scopy  telescopy
 tele.scopic  telescopic
 arrheno.toky  *
 deutero.toky  *
 thely.toky  *

* Not common enough for a consensus to have been reached.

The column headed "The way it is" shows the way that most Americans pronounce the word. Clearly, "the rule" works poorly with compound words that have roots in other languages, or at least in classical languages (most of these words) and Arabic (alchemy and algebra).

But did you notice something else about the words in column B? All have at least three syllables, and there is a strong tendency to place the stress on the antepenultimate syllable, and thus to forget about the etymology (origin and meaning). The same occurs in Spanish where the word telephone, which has three syllables in English, has four in Spanish (telefono) and the stress is on the antepenultimate. English does not require the stress in polysyllabic words to be on the antepenultimate (consider the words polysyllabic, and caterpillar where it is not), so it makes more sense to stress the word according to its etymology as in column A. Unfortunately, logic is not a virtue of English pronunciation.

The words discussed here are English, and the rules (such as they are) of English spelling, grammar, and pronunciation apply. In contrast, scientific names of species, genera, and higher categories are considered to be Latin, so rules of Latin spelling, grammar, and pronunciation apply to them (SECTION 10).