The x-system is a reversible way to represent Esperanto’s six diacritic letters when you can type only basic Latin characters. Add x after the base letter: cx represents ĉ, gx represents ĝ, and so on. Because x is not a letter of the Esperanto alphabet, the added character can act as an unambiguous conversion signal inside ordinary Esperanto words.
The x-system is extremely useful for keyboard input, plain-text channels, search boxes, and legacy data. It is not the normal appearance of finished modern Esperanto. When Unicode works, convert the code to ĉ, ĝ, ĥ, ĵ, ŝ, ŭ before publishing.
If you first need to configure direct character entry, start with typing Unicode Esperanto. The x-system is one route to those characters, not a reason to avoid them.
The complete mapping
| Unicode letter | x-system input | Uppercase input | Example |
|---|---|---|---|
| ĉ | cx | Cx or CX | cxu → ĉu |
| ĝ | gx | Gx or GX | gxi → ĝi |
| ĥ | hx | Hx or HX | ehxo → eĥo |
| ĵ | jx | Jx or JX | jxus → ĵus |
| ŝ | sx | Sx or SX | sxi → ŝi |
| ŭ | ux | Ux or UX | ankoraux → ankoraŭ |
Converters differ in their treatment of capitals. Many accept Cx for Ĉ and all-caps CX for Ĉ in an uppercase word. Test the tool you actually use rather than assuming every implementation has identical case rules.
Mi tajpas “Gxis morgaux!” kaj la programo montras “Ĝis morgaŭ!”
I type ‘Gxis morgaux!’ and the program displays ‘Ĝis morgaŭ!’ (x-system input converted to Unicode)
La enigita formo “sxangxi” fariĝas “ŝanĝi”.
The input form ‘sxangxi’ becomes ‘ŝanĝi’ (to change).
Why x makes conversion reliable
In native Esperanto vocabulary, x has no independent role. Therefore cx can be reserved for ĉ without colliding with an ordinary Esperanto sequence of c + x. This is the chief technical advantage over the h-system: combinations such as ch can occur across meaningful parts or in foreign material, while x clearly signals encoding in an Esperanto-only field.
The method also gives ŭ a unique code, ux. The foundational h-system writes ŭ simply as u, which can merge distinct spellings and cannot always be reversed automatically. The x-system is not part of the Esperanto alphabet; its usefulness comes precisely from that fact.
En x-sistemo, “caro” restas “caro”, sed “ĉaro” fariĝas “cxaro”.
In the x-system, caro (tsar) remains caro, but ĉaro (cart) becomes cxaro.
La konvertilo distingas “au” de “aux”: nur “aux” fariĝas “aŭ”.
The converter distinguishes au from aux: only aux becomes aŭ.
That is a technical minimal contrast. In standard Unicode Esperanto, the meaningful contrast is between the plain sequence au and the correctly spelled diphthong with ŭ, aŭ. The x-system preserves it during ASCII-only transmission.
Input layer, fallback layer, and orthography
Keep three levels separate:
- Orthography: the Esperanto word is spelled ĝis with ĝ.
- Input method: you may type gxis to make a converter produce ĝis.
- Technical fallback: if a channel genuinely cannot carry Unicode, you may transmit gxis and tell the recipient that the text uses the x-system.
The Academy’s foundationally specified substitute is the h-system. Later Academy guidance also permits other substitutions under special technical conditions when the correct letters cannot be used and the h-system is unsuitable, provided the substitution is merely technical, causes no confusion, and does not propose a spelling reform. That framework accommodates the x-system without turning x into Esperanto’s twenty-ninth letter.
The historically foundational alternative is described on the h-system. Comparing the two makes clear why x-spelling is easier for automatic round-trip conversion even though h-spelling has a different normative status.
In current (neutral) publication, Unicode is the expected output. X-system text remains common and intelligible in (technical/informal) contexts—for example, a search field configured to convert it or a message typed through an ASCII-only interface. A whole web article left in x-system despite full Unicode support looks unfinished and is harder to read.
Ĉu la serĉilo akceptas “jxurnalo” kaj trovas “ĵurnalo”?
Does the search engine accept jxurnalo and find ĵurnalo (newspaper)?
Ne publikigu la x-sisteman version antaŭ ol vi kontrolis la konverton.
Do not publish the x-system version before you have checked the conversion.
“Ĉu vi povas legi mian mesaĝon?” — “Jes, sed bonvolu konverti ĝin al Unikodo.”
“Can you read my message?” — “Yes, but please convert it to Unicode.”
This exchange shows the practical social distinction: x-system text may be readable without being the best final form.
A safe conversion workflow
First, identify the scope. Convert only text known to be Esperanto, not an entire mixed document indiscriminately. Then replace the six sequences, preserve capitalization, and inspect the result. Finally, search the output for leftover cx, gx, hx, jx, sx, and ux sequences.
Mi konvertis “Sxi jxus alvenis” al “Ŝi ĵus alvenis”.
I converted ‘Sxi jxus alvenis’ to ‘Ŝi ĵus alvenis.’
Post la konverto, ni kontrolis la vortojn “aŭskulti”, “ĝoji” kaj “freŝa”.
After conversion, we checked the words aŭskulti (to listen), ĝoji (to rejoice), and freŝa (fresh).
Why limit the scope? An unadapted name such as Max, a URL, a product code, or programming text can contain a genuine x. Some x-system tools define an escape convention such as doubled xx, but this is implementation-specific, not a universal Esperanto rule. Protect non-Esperanto segments or review them one by one.
Reading x-system text
When no converter is available, mentally collapse each marked pair into one letter. Read Mi gxojas, ke sxi venos as Mi ĝojas, ke ŝi venos. Do not pronounce an extra /ks/ after every base letter. Word boundaries and grammatical endings remain unchanged: amikojn needs no x because it contains no diacritic letter.
La x-sistema frazo “Mi gxojas, ke sxi venos” signifas “Mi ĝojas, ke ŝi venos”.
The x-system sentence ‘Mi gxojas, ke sxi venos’ means ‘I am glad that she will come.’
En “Cxu vi ankoraux atendas?”, la formoj “Cxu” kaj “ankoraux” reprezentas “Ĉu” kaj “ankoraŭ”.
In ‘Cxu vi ankoraux atendas?’ (Are you still waiting?), Cxu and ankoraux represent Ĉu and ankoraŭ.
X-system spelling does not change stress, morphology, or meaning. It encodes letters only. It also does not justify dropping uppercase distinctions or combining English capitalization with Esperanto prose.
Common Mistakes
1. Publishing raw x-system input as though it were standard spelling. Convert when Unicode is available.
❌ Sxi mangxas fresxan panon.
Incorrect as normal finished prose — the x-system codes remain unconverted.
✅ Ŝi manĝas freŝan panon.
She is eating fresh bread.
2. Adding x after every u. Only ŭ maps to ux; ordinary u remains u.
❌ La lumo estas bluxa.
Incorrect x-system encoding — the u in blua is an ordinary vowel, and the adjective ending is -a.
✅ La lumo estas blua.
The light is blue.
3. Converting mixed foreign material blindly. A genuine x in a name must be protected.
❌ La programo ŝanĝis la nomon Max al Maŝ.
Incorrect conversion — the foreign name Max contained a genuine x.
✅ La programo konservis la nomon Max kaj konvertis nur la Esperantan tekston.
The program preserved the name Max and converted only the Esperanto text.
4. Believing x is an Esperanto letter. It is a coding signal, so it does not receive a place in native alphabetic order.
❌ La litero x staras inter v kaj z en la Esperanta alfabeto.
Incorrect — x is absent from the Esperanto alphabet.
✅ La Esperanta alfabeto iras de v rekte al z.
The Esperanto alphabet goes directly from v to z.
5. Mixing systems inside one word. Use one encoding consistently until conversion.
❌ Mi skribis “ŝangxi” per du malsamaj sistemoj.
Incorrect — ŝ is Unicode but gx is still x-system input.
✅ Mi tajpis “sxangxi” kaj konvertis ĝin al “ŝanĝi”.
I typed sxangxi and converted it to ŝanĝi (to change).
Key Takeaways
- Map ĉ, ĝ, ĥ, ĵ, ŝ, ŭ to cx, gx, hx, jx, sx, ux when a technical input or fallback requires ASCII.
- X-system sequences represent single Esperanto letters and do not change pronunciation or grammar.
- The system is reversible because x is not a native Esperanto letter.
- Unicode remains the normal output; convert and proofread before publication.
- Protect foreign names, URLs, code, and other genuine x-containing strings during automatic conversion.
Now practice Esperanto
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Start learning Esperanto →Related Topics
- Typing Unicode EsperantoA1 — Practical ways to enter, verify, and publish the six Esperanto letters with their correct Unicode characters.
- The H-SystemA2 — How the Fundamento's fallback spelling represents Esperanto's six diacritic letters, and when modern writers should use it.
- Converting Legacy Text SafelyA2 — A reliable workflow for converting H-system, X-system, and damaged Esperanto text into reviewed Unicode spelling.
- The Six Diacritic LettersA1 — Master ĉ, ĝ, ĥ, ĵ, ŝ, and ŭ as six independent Esperanto letters with distinct sounds and spelling roles.
- Unicode Normalization and SearchA2 — Why visually identical Esperanto letters can behave differently in software, and how to store and search them reliably.