4 syllables: Chlor, pyr, i, fos. Stress on Chlor.
KLAWR-pir-if-os
/ˈklɔɹpɪɹɪfɒs/
Chlorpyrifos is pronounced KLAWR-pir-if-os (/ˈklɔɹpɪɹɪfɒs/). It has four syllables (Chlor-pyr-i-fos), with the stress on "Chlor". Chlorpyrifos is a synthetic organophosphate insecticide used to control a variety of pests on crops, ornamentals, and building materials. It is potent and effective but controversial due to health and environmental concerns. In speech, the term is encountered in technical papers, regulatory documents, and industry discussions, and it can be challenging due to multiple consonant clusters and the long, unfamiliar root.
nounChlorpyrifos is a synthetic organophosphate insecticide used to control a variety of pests on crops, ornamentals, and building materials. It is potent and effective but controversial due to health and environmental concerns. In speech, the term is encountered in technical papers, regulatory documents, and industry discussions, and it can be challenging due to multiple consonant clusters and the long, unfamiliar root.
How to Pronounce Chlorpyrifos
"The agricultural scientist discussed the residue analysis of chlorpyrifos in soil samples."
"Regulators initiated new guidelines on the safe handling of chlorpyrifos in farming operations."
"Chlorpyrifos was reformulated in several markets to reduce environmental impact."
Chlorpyrifos is pronounced with four syllables: /ˌklɔːrˈpɪrɪˌfoʊs/. Emphasize the second syllable stress on PİR, with a secondary emphasis on the fourth syllable. Start with /kl/ as a consonant blend, move to /ɔːr/ in the second syllable, then /˪pɪrɪ/ followed by /foʊs/. The dental-tongue position for /r/ and the rounded lips for /oʊ/ matter; keep the vowel quality long in the second and fourth syllables. Audio reference: you can listen to professional pronunciations on Pronounce or Forvo for corroboration.
Common errors include misplacing the stress (overemphasizing the first syllable) and mispronouncing the final -fos as /fæs/ instead of /foʊs/. A frequent slip is shortening the middle syllables leading to /ˈklɔrˌpɪrɪˌfɒs/ in UK/AU; aim for /ˌklɔːrˈpɪrɪˌfoʊs/. Practice ensuring the early cluster /kl/ remains tight, the /r/ is lightly voiced, and the final /oʊs/ has a clear diphthong rather than a short /ɒs/.
In US English, the first syllable uses /klɔːr/ with rhotic r and a longer /ɔː/; the second syllable carries primary stress: /ˈpɪrɪ/. In UK English, the /ɔː/ is slightly shorter, and the final /foʊs/ may be pronounced with less rounding in some regions, giving /ˈklɔːrˌpɪrɪˈfɒs/. Australian speakers tend to be rhotic with an even more centralized second vowel and a slightly raised final vowel, yielding /ˌklɔːˈpɪrɪˌfɒs/. All accents keep the terminal /s/ voiceless. Audio checks recommended.
The difficulty comes from the multi-syllabic length, the three consonant clusters in a row (/kl/ at the start and /rp/ near the middle), and the final /ɪfoʊs/ cluster that makes the last two syllables tricky to articulate quickly. The stress pattern also shifts—secondary stress on the third syllable can cause uncertainty. Focus on segmenting into four syllables and practicing each cluster slowly before speeding up; use IPA cues to align mouth positions.
Why does the word include two distinct vowel qualities in close succession (the /ɔː/ in the first syllable and the /ɪ/ in the third) and how should your mouth position adapt? The /ɔː/ is a long open-mid back rounded vowel requiring a rounded lip shape, while the /ɪ/ is a lax high front vowel that requires less jaw opening. Keep your tongue high in the back for /ɔː/ and shift to a higher, more fronted position for /ɪ/ without tensing the jaw.
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- US: Rhotic r; longer /ɔː/ in stressed syllable; final /s/ clear. - UK: Shorter /ɔː/; non-rhotic in some varieties, but chlorpyrifos usually pronounced with an r-like liquid in careful speech; final /s/ remains voiceless. - AU: Rhotic; vowel qualities softened toward /ɒ/ or /ɜː/ depending on speaker; keep /foʊs/ rounded but not overly; maintain clear /r/ where present. Across all, the key is the four-syllable rhythm and the /rp/ cluster. IPA references: /ˌklɔːrˈpɪrɪˌfoʊs/ US, /ˌklɔːˈpɪrɪˌfɒs/ UK/AU (approx).
Chlorpyrifos derives from a blend of chemical-structure-inspired morphemes. The prefix chlor- traces back to the chlorine atom, a common root in organochlorine pesticides. The -pyr- segment references a pyridine-like ring or related heterocycle motifs common in organophosphorus chemistry. The -ifos suffix is a conventional ending seen in some pesticide and organophosphate names, aligning with the -phos/-fos group meaning phosphorus-containing compounds (phosphates/organophosphates). The word entered scientific and regulatory vocabulary in the mid-20th century as synthetic organophosphates were developed for pest control, with early use in agriculture. It gained prominence in toxicology and public health discourse due to concerns about neurotoxicity and persistence in the environment. First known uses appear in agrochemical product labels and peer-reviewed articles around the 1950s–1960s, with widespread regulatory attention by the 1990s and 2000s as monitoring and risk assessment intensified. The name has since become a standard term in pesticide literature and regulatory treaties, often appearing in lists of restricted-use pesticides and environmental impact assessments.
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Words that rhyme with "Chlorpyrifos"
-mos sounds
-tos sounds
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