June theme: Pride In Words 🏳️‍🌈

Teaser

two, neodymium, duet, biceps, bi-, biscuit, duplicate, Maldives, doppelganger, icosahedron, twin, nonbinary

Full Text

• Proto-Indo-European *dwóh₁ two

  • Old Armenian երկու erku two ^[1]

    • Old Armenian կրկին krkin double, doubled, iterated

      • Armenian կրկին krkin double, again, once more
    • Armenian երկու erku two
  • Italic *duō two

    • Umbrian 𐌕𐌖𐌚 tuf two
    • Latin duo two

      • Eastern Romance

        • Romanian doi two
      • Western Romance

        • French deux two
        • Italian duo duo, two (archaic)

          • Italian due two

            • Italian duetto duet

              • English duet
          • English duo two
        • Spanish dos two
      • Sardinian duos two
  • Balto-Slavic *duwō two

    • Lithuanian du two
    • Slavic *dъva two

      • South Slavic

        • Serbo-Croatian два̑ dvȃ two
      • East Slavic

        • Russian два dva two
      • West Slavic

        • Polish dwa two
  • Proto-Indo-European *dwi(s)- two (prefix)

    • Indo-Iranian *dwi-

      • Indo-Iranian *dwiHpás island lit. "two-waters", water on both sides

        • Telugu ద్వీపము dvīpamu island

          • Telugu ద్వీపకల్పము dvīpakalpamu peninsula lit. "island-ish"
        • Hindi द्वीप dvīp island
        • Mongolian ᠲᠢᠢᠪ tiib continent
        • Thai ทวีป tá-wîip continent
        • Khmer ទ្វីប tviip continent
        • Sanskrit 𑀤𑁆𑀯𑀻𑀧 dvīpá island, continent

          • Magadhi

            • Assamese দীয়া dia island, sandbar, shoal
          • Elu

            • Dhivehi މާލެދިވެހި Malē Dhive Malē Islands, Maldives

              • English Maldives
            • Sinhala දිවයින diwayina island
            • Dhivehi ދިވެހި Dhivehi "Islander"

              • English Dhivehi
          • Pali 𑀤𑀻𑀧 dīpa island

            • Thai ทีป tîip island
    • Hellenic

      • Classical Greek δι- di- two, twice (prefix)

        • English di-
        • Classical Greek δῐ́δῠμος dídumos twin, double, twofold, Gemini di/duo-dúo-mo-s

          • Classical Greek Δίδυμος Dídumos Twin (personal name)
          • New Latin didymia one of two oxides isolated from cerium ^[2]

            • New Latin didymium

              • New Latin praseodidymium ^[2]

                • Translingual Pr
                • New Latin praseodymium

                  • English praseodymium
              • English didymium
              • New Latin neodidymium ^[2]

                • New Latin neodymium

                  • English neodymium
                • Translingual Nd
          • Greek δίδυμος dídymos twin, twinned, matching

            • Greek Δίδυμοι Dídymoi Gemini
    • Germanic *twi- two, double (prefix)

      • North Germanic

        • Old Norse tví-

          • Icelandic tví- two, double, binary
      • West Germanic

        • Old English twi- two, twice, double

          • Old English twilic double threaded, twill with translation of bi- to native twi-

            • English twill
          • Old English twīlēoht twilight

            • English twilight
        • Old High German

          • German zwei-

            • German Zweihänder two handed sword

              • English zweihander
    • Proto-Indo-European *dwi(h₁)dḱm̥ti twenty (two-ten)

      • Old Armenian քսան kʿsan twenty

        • Armenian քսան kʿsan twenty
      • Celtic *wikantī twenty

        • Brythonic *gwɨgėnt twenty

          • Welsh ugain twenty
        • Old Irish fiche twenty

          • Irish fiche twenty

            • Irish daichead forty, two-score
      • Italic

        • Latin vīgintī twenty

          • Latin vīcēsimu twentieth

            • English vigesimal
          • Sardinian binti twenty
          • Western Romance

            • Spanish veinte twenty
            • French vingt twenty

              • Haitian Creole ven twenty
            • Italian venti twenty
      • Balto-Slavic

        • Lithuanian dvidešimt twenty
      • Proto-Albanian *wdžáti twenty

        • Albanian -zet twenty (in compounds)

          • Albanian njëzet twenty lit. "one-twenty"
      • Indo-Iranian *HwiHĉati

        • Indo-Aryan *HwiHśati

          • Dardic

            • Kashmiri وُہ vuh twenty
          • Sanskrit 𑀯𑀺𑀁𑀰𑀢𑀺 viṃśatí

            • Maharashtri 𑀯𑀻𑀲𑀇 vīsaï

              • Marathi वीस vīs
            • Sauraseni

              • Western Sauraseni

                • Romani biś twenty
              • Madhya Sauraseni

                • Hindi बीस bīs twenty
              • Pahari

                • Punjabi ਵੀਹ vīh twenty
            • Magadhi

              • Bengali বিশ bish twenty
            • Pali vīsati
        • Iranian *HwiHĉati

          • Avestan 𐬬𐬍𐬯𐬀𐬌𐬙𐬌 vīsaⁱti twenty
          • Western Iranian

            • Old Persian

              • Persian بيست bist twenty
            • Kurdish bîst twenty
          • Northern Iranian

            • Scythian *insæǰ

              • Ossetian ссӕ́дз ssǽʒ twenty
      • Tocharian *w'īkän twenty

        • Arshian wiki twenty
        • Kushean ikam twenty
      • Hellenic ewīkəti

        • Classical Greek εἴκοσῐ eíkosi twenty

          • Classical Greek εἰκοσάεδρον eikosáedron solid shape with twenty sides, icosahedron

            • English icosahedron
          • Greek είκοσι eíkosi twenty
    • Italic *dwi(s)-

      • Italic ​​*dwipleks two-fold, double

        • Latin duplex

          • English duplicity
          • Latin duplicō I double, I duplicate, I fold in half, I split in half, I enlarge

            • English duplicate
          • English duplex
      • Latin bi(s)- two parts, twice (prefix)

        • Latin bilanx double-pan, balancing scale

          • French balance

            • English balance
        • Western Romance

          • French bi-
          • Italian bi(s)-
          • English bi-
          • Spanish bi(s)-
          • Western Romance *biscoctu "twice-cooked"

            • Italian biscotto

              • English biscotti
            • Spanish bizcocho
            • French biscuit

              • English biscuit
        • Latin bilix double threaded

          • Old English twilic double threaded, twill with translation of bi- to native twi-

            • English twill
        • Latin biceps two-headed, double-edged, in two parts

          • English biceps
    • Proto-Indo-European *dwís

      • Italic *dwis

        • Latin bis twice
      • Albanian dysh double
      • Hellenic *dwis

        • Classical Greek δίς dís
      • Indo-Iranian *dwíš

        • Indo-Aryan *dwíṣ

          • Sanskrit 𑀤𑁆𑀯𑀺𑀲𑁆 dvis twice
        • Iranian *dwíš

          • Avestan 𐬠𐬌𐬱 biš
    • Anatolian

      • Lycian kbi- other, another, second
      • Luwian twi- two, double
    • Proto-Indo-European *dwiploh₁us two-filled, double, ambivalent, doubtful

      • Germanic *twīflaz doubt

        • East Germanic

          • Gothic 𐍄𐍅𐌴𐌹𐍆𐌻 tweifl doubt
        • West Germanic

          • Old High German zwīfal doubt

            • German Zweifel doubt
          • Frankish

            • Dutch twijfel doubt
          • Old Saxon

            • Middle Low German twīvel doubt

              • Danish tvivl doubt
      • Hellenic

        • Classical Greek δῐπλόος diplóos two-fold, folded in half, double, compound, doubtful

          • Classical Greek δῐ́πλωμᾰ díplōma doubled thing, folded paper, double pot

            • Latin diplōma letter of recommendation, diploma

              • English diploma
              • Latin diplōmaticus related to a letter of recommendation, diplomatic

                • French diplomatique

                  • French diplomate diplomat back-formed

                    • English diplomat
                  • English diplomatic
          • Greek διπλός diplós two-fold, double, dual
      • Italic *dwiplos

        • Latin duplus double

          • Western Romance

            • Spanish doble
            • French double

              • German doppeln to double

                • German doppel-

                  • German Doppelgänger

                    • Japanese ドッペルゲンガー dopperugengā
                    • English doppelganger
              • English double
            • Italian doppio
          • English duple
    • Proto-Indo-European *dwino-s pair, twin

      • Balto-Slavic

        • Lithuanian dvynys twin
        • Slavic

          • East Slavic

            • Russian дво́йня dvójnja twins
      • Italic

        • Latin bīnus double, in pairs

          • Latin combīnō I combine, I put together a pair

            • Western Romance

              • French combiner to combine

                • English combine
              • Spanish combinar to combine, to go with
              • Italian combinàre to combine, to match, to organize, to achieve
          • Latin bīnārius containing two things

            • English binary

              • English nonbinary
          • Vulgar Latin *bināre to do twice

            • Western Romance

              • Spanish binar to plow over
              • Italian binare to repeat, to double
              • French biner to hoe, to attend mass twice in one day
      • Germanic *twinaz twin, pair, double

        • West Germanic

          • Old English twinn twin

            • English twin
        • Germanic *twinlingaz twin children

          • West Germanic

            • Old High German zwinilinc
            • German Zwilling twin
            • Frankish *twinling

              • Dutch tweeling twin, pair of twins
          • North Germanic

            • Old Norse *tvinlingr

              • Danish tvilling twin
        • North Germanic

          • Old Norse tvinnr

            • Icelandic tvennur pair
    • Proto-Indo-European *dwisnó-s paired, doubled

      • Germanic *twiznaz twine, double thread

        • West Germanic

          • Old English twīn

            • English twine
          • Old High German zwirn

            • German Zwirn thread, string, yarn
  • Tocharian

    • Arshian wu two
    • Kushean wi two
  • Celtic *dwau two

    • Brythonic *dọw two

      • Welsh dau two
    • Old Irish dau two

      • Irish dó two
  • Proto-Indo-European *dwoyóm acc.?

    • Anatolian

      • Hittite tān
  • Albanian dy two
  • Hellenic *dúwō two

    • Classical Greek δύο dúo two

      • Greek δύο dúo two
      • Classical Greek δῐ́δῠμος dídumos twin, double, twofold, Gemini di/duo-dúo-mo-s

        • Classical Greek Δίδυμος Dídumos Twin (personal name)
        • New Latin didymia one of two oxides isolated from cerium ^[2]

          • New Latin didymium

            • New Latin praseodidymium ^[2]

              • Translingual Pr
              • New Latin praseodymium

                • English praseodymium
            • English didymium
            • New Latin neodidymium ^[2]

              • New Latin neodymium

                • English neodymium
              • Translingual Nd
        • Greek δίδυμος dídymos twin, twinned, matching

          • Greek Δίδυμοι Dídymoi Gemini
  • Germanic *twai two

    • West Germanic

      • Old English twā

        • Old English twēġen

          • English twain
        • Old English tweowes twice adverb

          • English twice
        • English two
      • Frankish *twē two

        • Dutch twee two
      • Old High German zwei two

        • Yiddish צוויי tsvey two
        • German zwei two
    • East Germanic

      • Gothic 𐍄𐍅𐌰𐌹 twai two
    • Germanic *twai-tigiwiz two group-of-tens, twenty

      • North Germanic

        • Old Norse tuttugu twenty

          • Icelandic tuttugu twenty
          • Danish tyve twenty
      • East Germanic

        • Gothic 𐍄𐍅𐌰𐌹 𐍄𐌹𐌲𐌾𐌿𐍃 twai tigjus twenty
      • West Germanic

        • Old High German zweinzug

          • German zwanzig twenty
          • Yiddish צוואַנציק tsvantsik twenty
        • Old English twēntiġ

          • English twenty
        • Frankish *twēntig

          • Dutch twintig twenty
    • North Germanic

      • Old Norse tvau two

        • Icelandic tvö two
        • Danish to two
  • Indo-Iranian

    • Iranian *duu̯a two

      • Avestan 𐬛𐬎𐬎𐬀 duua two
      • Northern Iranian

        • Scythian

          • Ossetian дыууӕ dywwæ two
      • Western Iranian

        • Old Persian

          • Persian دو do two
        • Kurdish du two
      • Pashto دوه dwa two
    • Indo-Aryan *dva two

      • Dardic

        • Kashmiri zɨ two
      • Sanskrit 𑀤𑁆𑀯 dvá two, both

        • Malay dwi two
        • Elu

          • Sinhala දෙක deka two
        • Magadhi

          • Bengali দুই dui two
        • Sauraseni 𑀤𑁄 do two

          • Western Sauraseni

            • Romani duj two
          • Madhya Sauraseni

            • Hindi दो do two
          • Pahari

            • Punjabi ਦੋ do two
        • Telugu ద్వయము dvayamu two, pair
        • Pali dve two

          • Thai โท too second

Visual

Collected English words

two, twain, twice, twenty, didymium, neodymium, Nd, praseodymium, Pr, duo, duet, twilight, zweihander, di-, twill, biceps, balance, bi-, biscuit, biscotti, duplex, duplicate, duplicity, Dhivehi, Maldives, diploma, diplomatic, diplomat, double, doppelganger, duple, icosahedron, vigesimal, twine, twin, binary, nonbinary, combine

Footnotes

1. ^

   Armenian երկու erku from *dwóh₁ is the type specimen of "The Proto-Armenian sound changes are varied and eccentric (such as *dw- yielding erk-)" https://en.wikipedia.org/wiki/Proto-Armenian_language#Development

2. ^

   Around 1840, Swedish chemist Carl Gustaf Mosander isolated the oxide ceria into two separate oxides, which he called lanthana ("hidden, forgotten" related to Lethe) and didymia ("twin"). Lanthana was determined to be an elemental oxide of a new element lanthanum. Didymia was then separated into samarium and didydium, and finally didymium was separated into the elements neo(di)dymium and praeso(di)dymium.

   So while neodymium and praesodymium form a "twin" set of elements, that is not the pair of twins their names refer to, but to twin discovery of lanthanum and didymium.