Expanding Vocabulary: The Cognate Method (Part 1)

All Parts

  • Part 1 (Introduction, Words ending in -al)
  • Part 2 (Words ending in -ion, Words beginning with dys-/des-/dis-)
  • Part 3 (Words ending in -ant or -ent, Words ending in -ible or -able)
  • Part 4 (Words ending in -ic, Words ending in -ence or -ance)
  • Part 5 (Words ending in -ist or -ism, Miscellaneous)


(Skip to the next section if you don't want background on the methodology being used here.)

One of the most useful skills to pick up when learning a language that is related to one you already know, is figuring out ways to "guess" words that might exist in your target language, based on patterns. Esperanto's vocabulary is 75% based on Latin and Romance languages, 20% from Germanic languages and the remaining are loan words from Slavic and other language families. English speakers are in luck then, because English is a Germanic language with a ton of influence from Latin and Romance languages - the trick is figuring out some rules for stumbling on new vocabulary.

I'm going to make a series of posts where I explain some rules of thumb for finding Esperanto words based on English ones. None of these rules rules work 100% of the time, and sometimes even when related words do exist they mean different things from English (check here and here if you're worried about false friends), but hopefully I can give other learners useful tools for painlessly expanding their vocabulary in Esperanto.

Esperanto words can be based on the spelling or sound of a word, or a compromise of the two - so don't be surprised if "th" becomes "t", letters that have many sounds in English like "c" somtimes become "k", or if words with "g" in them can become "g" or "ĝ" in Esperanto. Remember that Esperanto doesn't have q, w, x, and y - so these will always become different letters in Esperanto (usually qu=kv, w=v/ŭ, x=ks, and y=j/i.)

First Rule of Thumb: English Words Ending in -al

Many English words that end in -al have an equivalent in Esperanto. Some retain the -al, becoming -ala or -alo (depending on whether the word is an adjective or noun), while others drop it entirely instead having an -a or an -o. Words that end in -ical sometimes drop the -ic, the -al, or the entire -ical. Here are some examples (where the equivalent form is not the base word, I also include that afterwards):

  • animal - animalo [note: this word is rare outside of science texts, use "besto" instead.]
  • apocryphal - apokrifa | apokrifo (apocrypha)
  • archeological - arĥeologia, arkeologia | arĥeologio (archeology) [note: "ch" in a lot of latin-based words becomes ĥ or k in esperanto]
  • banal - banala
  • botanical - botanika | botaniko (botany)
  • canal - kanalo
  • cannibal - kanibalo
  • canonical - kanona | kanono (big gun / religious canon)
  • capital (wealth assets) - kapitalo
  • cathedral - katedralo
  • ceremonial - ceremonia | ceremonio (ceremony)
  • classical - klasika
  • colonial - kolonia | kolonio (colony)
  • coral - koralo
  • cultural - kultura | kulturi (to cultivate, to culture)
  • decimal - decimala
  • dental - denta | dento (tooth)
  • diagonal - diagonala, diagonalo
  • fatal - fatala | fatalo (fate)
  • festival - festivalo
  • formal - formala
  • general - ĝenerala (overall), generalo (military officer)
  • horizontal - horizontala, horizontalo
  • ideal - idealo, ideala
  • imperial - imperia | imperio (empire)
  • individual - individuo, individua
  • legal - leĝa | leĝo (law)
  • liberal - libera (free), liberala (politically liberal)
  • loyal - lojala
  • material - materialo, materiala (materials used to make something), materio (matter, as opposed to spirit / substance)
  • metal - metalo
  • moral - morala | moralo (morality)
  • natural - natura
  • neanderthal - neandertalo
  • neutral - neŭtrala
  • nominal - nominala
  • normal - normala
  • official - oficiala
  • original - originalo, originala
  • pedal - pedalo
  • personal - persona | persono (person)
  • radical - radikala
  • special - speciala
  • universal - unversala
  • vandal - vandalo
  • virtual - virtuala

Some words that are near matches:

  • aerial - aera | aero (air)
  • anal - anusa | anuso (anus)
  • appeal (in court) - apelacii
  • approval - aprobo | aprobi (to approve)
  • axial - aksa | akso (axis, axle)
  • carnival - karnavalo
  • chemical (related to chemicals) - ĥemia, kemia | ĥemio (chemistry)
  • equal - egala
  • social - socia | socio (society)
  • total -tuta, tuto
  • viral - virusa | viruso (virus)
  • visual - vida | vidi (to see)

Two false friends to watch out for:

  • aktuala: topical, current, present(-day)
  • eventuala: contingent
August 19, 2019


note: "ch" in a lot of latin-based words becomes ĥ or k in esperanto

AFAIK those Latin-derived words are all originally Greek-derived, from the Greek letter χ.

August 19, 2019

You are 100% correct, a quick Google search shows that the etymology of "archeology" is:

early 17th century (in the sense ‘ancient history’): from modern Latin archaeologia, from Greek arkhaiologia ‘ancient history’, from arkhaios ‘ancient’. The current sense dates from the mid 19th century.

August 19, 2019

these words looks like it's in portuguese lol

August 24, 2019
Learn Esperanto in just 5 minutes a day. For free.