diphthong
/ˈdɪfˌθɒŋ(ɡ)/
"diphthong" is a 9-letter English headword indexed on PlainSpell.
The verdict
“diphthong” is uncommon English (frequency #85,178 among 26,416 “D” headwords), classed as a noun. The kind of spelling people second-guess.
- #85,178
- frequency rank, English
- 26,416
- “D” headwords
According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - A complex vowel sound that begins with the sound of one vowel and ends with the sound of another vowel, in the same syllable.
| Property | Value |
|---|---|
| Headword | diphthong |
| Language | English |
| Part of speech | Noun |
| IPA | /ˈdɪfˌθɒŋ(ɡ)/ |
| Letters | 9 |
| Frequency rank | #85,178 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “diphthong” sits in English frequency
Rare enough to double-check
diphthong is uncommon English at frequency #85,178 among 26,416 “D” headwords, classed as anoun, transcribed /ˈdɪfˌθɒŋ(ɡ)/. Rarity is why readers land here mid-draft. 3 senses are on record.
We couldn't generate a plausible misspelling set for diphthong, typically a sign the spelling maps closely to how the word sounds. This entry stands alone in our confusable dataset, suggesting its spelling stands apart enough that readers rarely confuse it with something else.
Etymologically, the entry records: PIE word *dwóh₁ From French diphtongue, from Late Latin diphthongus, from Ancient Greek δίφθογγος (díphthongos, “two sounds”), from δίς (dís, “twice”) + φθόγγος (phthóngos, “sound”). The correct English form is diphthong, spelled D-I-P-H-T-H-O-N-G.
Definition
- 1A complex vowel sound that begins with the sound of one vowel and ends with the sound of another vowel, in the same syllable.
- 2A diaphoneme realized as a two-target vowel in some but not necessarily all dialects.
- 3A vowel digraph or ligature.
Etymology
PIE word *dwóh₁ From French diphtongue, from Late Latin diphthongus, from Ancient Greek δίφθογγος (díphthongos, “two sounds”), from δίς (dís, “twice”) + φθόγγος (phthóngos, “sound”).
This word in other languages
Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.
Frequently Asked Questions
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Using “diphthong”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is D-I-P-H-T-H-O-N-G - every other letter order is a misspelling in standard orthography.
- Say it as /ˈdɪfˌθɒŋ(ɡ)/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
- Browse more English words and confusable pairs in the same reference. English words
Other uncommon English words near this rank
Data Source
Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.