An assimilated loanword is not foreign spelling dropped unchanged into an Esperanto sentence. It has entered Esperanto’s own system: it uses the 28-letter alphabet, follows regular sound–letter values and penultimate stress, takes an Esperanto grammatical ending where required, and supports ordinary Esperanto derivation.
The Fundamento’s Rule 15 licenses widely international words after adaptation to Esperanto orthography, then directs speakers to build derivatives from the adopted root. That principle encourages international recognizability without making English—or any other single national language—the automatic source of truth.
What full assimilation changes
Compare English spellings with established Esperanto words:
| International concept | Esperanto form | What adaptation shows |
|---|---|---|
| taxi | taksio | x becomes the Esperanto sequence ks; noun ends in -o |
| jazz | ĵazo | the initial /ʒ/-type sound is written ĵ; doubled z is unnecessary |
| chocolate | ĉokolado | /tʃ/ is written ĉ; the word takes Esperanto form |
| shampoo | ŝampuo | English sh becomes the single letter ŝ |
| museum | muzeo | regular Esperanto vowels and noun ending |
| garage | garaĝo | ĝ represents the final affricate sound in the adopted form |
| theatre | teatro | transparent Esperanto spelling and -o |
| blog | blogo | the root accepts an Esperanto noun ending |
These are (neutral) Esperanto words, not quotations from English. You read taksio from its letters, with s pronounced /s/ and i forming its own vowel nucleus; you do not reproduce the spelling or stress of English taxi.
La taksio atendas antaŭ la muzeo.
The taxi is waiting in front of the museum.
Post la filmo ni manĝis ĉokoladan kukon en la kafejo.
After the film, we ate chocolate cake in the café.
La ĵazgrupo koncertos en la hotelo vendrede.
The jazz group will perform at the hotel on Friday.
The 28-letter filter
Ordinary Esperanto words do not contain q, w, x, or y. An assimilated form replaces those letters with Esperanto spellings appropriate to the adopted pronunciation: x → ks in teksto and taksio, qu → kv in kvizo, and English sh → ŝ in ŝampuo. The result is readable to someone who does not know the donor language.
Ni faris mallongan kvizon pri la teksto.
We took a short quiz about the text.
Ŝi aĉetis ŝampuon kaj poste iris al la garaĝo.
She bought shampoo and then went to the garage.
The six Esperanto letters ĉ, ĝ, ĥ, ĵ, ŝ, ŭ are available when an established form requires them. Avoiding a diacritic by reverting to English digraphs breaks the one-letter–one-basic-sound design.
Post la matenmanĝo mi viŝis la buŝon kaj kuris al la buso.
After breakfast, I wiped my mouth and ran to the bus.
Buŝo and buso form a minimal contrast between ŝ and s. The borrowed buso has been fully integrated, and its spelling participates in exactly the same phonemic contrasts as inherited or internally formed vocabulary.
Add the grammatical ending
Most lexical roots cannot stand alone as ordinary words. An assimilated noun takes -o, an adjective -a, an adverb -e, and a verb an appropriate verbal ending. The ending reveals the word’s role just as it does with any other root.
La blogo estas nova, sed la aŭtoro jam blogas ĉiutage.
The blog is new, but the author already blogs every day.
La teatra grupo prezentos modernan dramon.
The theatre group will present a modern drama.
The adopted root teatr- produces teatro, teatra, teatre. Following Rule 15’s logic, derive from that Esperanto root rather than importing a second national-language form for each member of the family.
La fotografisto fotografis la historian monumenton.
The photographer photographed the historic monument.
Here fotograf- participates in Esperanto morphology: fotografo/fotografisto, fotografia, fotografi. Which derivative is conventional remains a vocabulary question; productive grammar does not guarantee that every logically possible form is equally common.
Do not borrow from English automatically
“International” does not mean “familiar to an English speaker.” Before coining a loan, check an authoritative dictionary, the Akademia Vortaro, and corpus usage. Esperanto may already have a conventional international root, a transparent compound, or a different semantic division.
For example, komputilo is the established ordinary word for “computer,” transparently built from komputi + -ilo. Importing computer as a new root would add needless competition. Likewise, English spelling often hides pronunciation; copying it would introduce silent letters and unstable values that Esperanto deliberately avoids.
Mi konservis la dokumenton en mia komputilo.
I saved the document on my computer.
New technical terms may remain (technical) before community usage settles. Honest writing distinguishes an attested established form from a personal proposal. The Akademio’s official additions record some roots, while Tekstaro reveals actual distribution; neither source licenses guessing solely from English.
Loanword, foreign word, or proper name?
An assimilated common noun such as hotelo is lowercase and takes Esperanto endings. An unassimilated title, trademark, quotation, or personal name may preserve foreign letters and capitalization because it remains a foreign-form token. A partially or fully Esperantized proper name follows its established convention.
Ni tranoktis en hotelo proksime al Times Square.
We stayed in a hotel near Times Square.
Hotelo is assimilated Esperanto; Times Square is retained as a foreign proper name. That contrast does not add q to the Esperanto alphabet.
— Ĉu mi esperantigu la nomon de la firmao? — Ne sen bezono; konservu ĝian oficialan nomon.
— Should I Esperantize the company’s name? — Not without a reason; preserve its official name.
This page concerns assimilated vocabulary; the recognition and inflection of names belong on foreign names in Esperanto.
Stress and syllables after assimilation
Once integrated, the word follows Esperanto stress: the penultimate vowel nucleus is stressed. Te-A-tro is not modeled on every national pronunciation of “theatre”; mu-ZE-o, ho-TE-lo, and ga-RA-ĝo follow their written Esperanto shapes. Each vowel letter counts as a vowel nucleus unless it participates in a separately explained sequence involving j or ŭ.
La nova restoracio apud la teatro malfermiĝos morgaŭ.
The new restaurant beside the theatre will open tomorrow.
Unicode and input fallbacks
Write assimilated words in Unicode: ĵazo, ŝampuo, ĉokolado, garaĝo. The h-system is a (Fundamental fallback) and the x-system a (technical input convention). Forms such as jxazo and sxampuo may be temporary keyboard input, but they are not polished modern spelling.
Common Mistakes
1. Keeping foreign letters inside an assimilated common noun. Use the established Esperanto form.
❌ Mi prenis taxion al la centro.
Incorrect — the English x remains inside what is meant as an Esperanto word.
✅ Mi prenis taksion al la centro.
I took a taxi to the center.
2. Copying an English digraph instead of an Esperanto letter. Sh does not replace ŝ in Unicode prose.
❌ Mi bezonas novan shampuon.
Incorrect as normal spelling — sh has replaced the Esperanto letter ŝ.
✅ Mi bezonas novan ŝampuon.
I need a new shampoo.
3. Omitting the Esperanto grammatical ending. The adopted root must form a complete word.
❌ La novan blog mi legis hieraŭ.
Incorrect — the noun root lacks -o, and agreement is disrupted.
✅ La novan blogon mi legis hieraŭ.
I read the new blog yesterday.
4. Preserving donor-language stress or silent letters. Read the Esperanto spelling.
❌ Mi donas al hotelo la anglan prononcon de hotel.
Incorrect — applying the English word’s pronunciation to hotelo.
✅ Mi prononcas hotelo laŭ ĝiaj Esperantaj literoj kaj akcentas te.
I pronounce hotelo from its Esperanto letters and stress te.
5. Publishing raw x-system codes. Convert input to the actual diacritic letters.
❌ La programo reklamas jxazon kaj cxokoladon.
Incorrect as finished prose — x-system codes remain unconverted.
✅ La programo reklamas ĵazon kaj ĉokoladon.
The program advertises jazz and chocolate.
Key Takeaways
A fully assimilated loan belongs to Esperanto: 28-letter spelling, stable sound values, penultimate stress, grammatical endings, and productive derivation. Prefer an established root over an English-shaped invention, distinguish common vocabulary from retained foreign names, and convert any h-system or x-system input to Unicode before publication.
Related Topics
- The Esperanto AlphabetA1 — Learn Esperanto’s 28 letters, their names and order, and why the six diacritic letters count as letters in their own right.
- Foreign Names in EsperantoA2 — How to choose among full adaptation, partial adaptation, and original spelling while keeping names recognizable and usable.
- Reading New Words AloudB1 — A repeatable procedure for turning any unfamiliar Esperanto spelling into clear, correctly stressed speech.
- Roots and Grammatical EndingsA2 — See how Esperanto combines meaningful roots with noun, adjective, adverb, and verb endings to create usable words.
- International Roots and False FriendsC1 — Use international Esperanto roots through Esperanto morphology while avoiding familiar-looking English cognates whose meanings, boundaries, or word families differ.
- Building Word FamiliesA2 — Build related Esperanto words step by step from a shared root while preserving category, scope, and conventional meaning.