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Esperanto grammar

CEFR A1

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Test yourself (22 questions)

Esperanto Letter Names: How to Spell Aloud (bo, co, ĉo)

By Michael McGettrickUpdated 11 October 2026

letter names follow one rule: a vowel names itself, and a consonant is its sound plus o. So b is bo, ĉ is ĉo and ŭ is ŭo.

Letter typeRuleExamples
vowelits own namea, e, i
consonantsound + obo, ĉo, ŭo

Quick check

Now use it: three quick questions on the chart above. The full practice is further down.

Pick the right one

0/3

Two claims about spelling aloud. Pick the true one.

  1. (about the letter ŭ)

  2. (about a radio alphabet)

  3. (about the o in bo)

  • ? - How is your name spelt?

The 28 names

The vowels:

LetterName
aa
ee
ii
oo
uu

The consonants, in alphabetical order:

LetterNameLetterName
bbokko
ccollo
ĉĉommo
ddonno
ffoppo
ggorro
ĝĝosso
hŝŝo
ĥĥotto
jjoŭŭo
ĵĵovvo
zzo

These are the Fundamento's names. PMEG's advice is to keep to them, because they are the only ones every speaker knows. Ŭ is a separate letter from u: u is a vowel and names itself, ŭ is a glide and takes -o like any consonant.

Spelling a word aloud

Say the names in order. The name already carries the hat, so ĉo and co cannot be confused:

WordSpelt aloud
ĉo, u
ŝo, i
a, ŭo
ho, o, mo, o

If only the hat is in doubt, add ĉapelita (hatted): co ĉapelita.

The o is a helper, not an ending

The o in bo is there because b alone cannot be pronounced. It is not the noun ending, PMEG points out, so a letter name does not take -j like a noun. To make a plural, add a real -o ending to the letter itself, joined with a hyphen, then -j or -n:

  • b-oj - two s (said bo-oj)
  • a-oj - three a's

Or leave the name bare, with no ending at all:

  • b - with two s

Is there a radio alphabet?

Not officially, but there is a standard choice: the spelling alphabet PMEG records as used by the UEA, for a noisy phone line where bo and po blur:

LetterWordLetterWord
aAsfaltok
bl
cm
ĉn
do
ep
fr
gGumos
ĝŝo
ht
ĥu
iŭ-
jJubileov
ĵzZinko

-, universe-hook, for ŭ names the letter after u plus its little hook. For letters outside the alphabet (q, w, x, y), PMEG says to use their full Esperanto names. On the air, radio amateurs use the ordinary international alfa-bravo-charlie alphabet.

Mistakes English speakers make

WrongRightWhy
bee, see (English)bo, coconsonants are sound + o
u for ŭŭotwo different letters
boj (two b's)b-ojPMEG: the o is not an ending

What to do next

  1. Spell your own name aloud with the Esperanto names.
  2. Recite the alphabet once: a, bo, co, ĉo, do...
  3. Then read how to type the hatted letters.

See also

Practise: test yourself

Sort into groups

0/6

Does the letter name itself, or add o?

Tap a word, then the group it belongs in.

Matching

0/8

Match each letter to the way you say it aloud. The vowels name themselves; every consonant is its sound plus an o.

Build the word

0/3

Build the letter name: the letter, then the helper o.

  1. the name of ĝ

    Accents optional - cx, gx, ux work for ĉ, ĝ, ŭ

    Your word is empty.

  2. the name of ŝ

    Accents optional - cx, gx, ux work for ĉ, ĝ, ŭ

    Your word is empty.

  3. the name of ĥ

    Accents optional - cx, gx, ux work for ĉ, ĝ, ŭ

    Your word is empty.

Pick the right one

0/3

Two claims about spelling aloud. Pick the true one.

  1. (about the letter ŭ)

  2. (about a radio alphabet)

  3. (about the o in bo)

Translation drill

0/2

Translate into Esperanto.

  1. How do you spell that word?

  2. The alphabet has twenty-eight letters.

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Frequently asked questions

How do you say the letters of the Esperanto alphabet?
Vowels name themselves: a, e, i, o, u. Every consonant is its sound plus o: bo, co, ĉo, do, fo, go, ĝo, ho, ĥo, jo, ĵo, ko, lo, mo, no, po, ro, so, ŝo, to, ŭo, vo, zo. These are the names in the , and PMEG advises keeping to them because they are the only ones every speaker knows.
How do you spell a word aloud in Esperanto?
Say the letter names in order: Berto is bo, e, ro, to, o. If only the hat is in doubt, say the letter name, which already carries it (ĉo, not co), or add ĉapelita, hatted. ? asks how your name is spelt.
What is the plural of a letter name in Esperanto?
PMEG's answer: the o in bo is a pronunciation helper, not the noun ending, so you add a real -o to the letter itself and then -j or -n: b-oj (said bo-oj), two s; a-oj, three a's. You can also leave the name bare: b, with two s. PMEG advises against boj, which treats the helper as an ending.
Is ŭ a different letter from u in Esperanto?
Yes. U is a vowel and names itself, u; ŭ is a consonant-like glide, named ŭo like the other consonants. They are separate letters of the 28, and ŭ appears almost only after a and e: , , .
Is there an Esperanto radio alphabet?
Not one with official standing. PMEG records the spelling alphabet the UEA uses (Asfalto, , , ...), with - for ŭ, and that is the one to use on a bad phone line. On the air, radio amateurs use the ordinary international alfa-bravo-charlie alphabet.