What is Pe̍h-ōe-jī?

A beginner-friendly guide to the romanisation system POJ Composer is built for — and why a tool like this exists at all.

The short version

Pe̍h-ōe-jī (白話字, literally “vernacular writing”, abbreviated POJ) is a way of writing Southern Min — the language family that includes Taiwanese Hokkien, Amoy, and Penang Hokkien — using the Latin alphabet plus a small set of tone marks. Instead of Chinese characters, a word like “Taiwanese person” is written Tâi-oân lâng. The little hats and bars over the vowels are tone marks, and getting them onto the right letter is exactly the chore this site removes.

A little history

POJ was developed by Western missionaries working in southern Fujian and among the Hokkien-speaking diaspora in the 19th century. The first systematic descriptions appeared in the 1830s–1850s, and by the late 1800s POJ was being used to print Bibles, dictionaries, and the Taiwan Church News — one of the longest-running romanised newspapers in the region. For generations of speakers, POJ was the first practical way to read and write their own spoken language, since Chinese characters do not map cleanly onto colloquial Hokkien.

Today POJ remains widely used by language learners, linguists, dictionary makers, and communities keeping Hokkien alive — including in Taiwan, Xiamen, and across Southeast Asia such as Penang, Malaysia. Modern standards (like Taiwan’s Tâi-lô) are closely related and share the same basic idea.

How the spelling works

Each syllable is built from up to three parts plus a tone:

  • An initial consonant (optional): p, ph, m, b, t, th, n, l, k, kh, g, ng, h, ch, chh, j, s.
  • A vowel or vowel cluster: a, e, i, o, u and combinations like ai, au, ia, oa. A couple of special vowels carry a dot — o͘ and e͘.
  • An ending (optional): a nasal ⁿ, or a final consonant m, n, ng, p, t, k, h.
  • A tone, shown by a diacritic on the main vowel.

So lâng = initial l + vowel a (with the tone-5 circumflex) + ending ng. The full set of tones is laid out on the tone marks page.

Why typing POJ is a pain

Two things make POJ awkward on a normal keyboard. First, the tone marks are combining diacritics that have to sit on the correct vowel of a cluster — for example the tone in oa goes on different letters depending on whether the syllable is open or closed. Second, the dotted vowels o͘ and e͘ use a rare combining character (U+0358) that most fonts misplace or drop entirely, and that many input methods can’t produce at all.

The result: people resort to copy-pasting characters, fighting with their OS’s accent menus, or just writing tone numbers and hoping the reader works it out.

How POJ Composer helps

POJ Composer lets you type a plain-ASCII numbered spelling and converts it to correct, tone-marked POJ as you go. You write the tone as a digit after each syllable, and the app places the diacritic on the right vowel automatically:

  • Goa2 si7 Tai5-oan5 lang5 → Góa sī Tâi-oân lâng
  • Peh8-oe7-ji7 → Pe̍h-ōe-jī
  • oo → o͘  ·  ee → e͘

Spaces, hyphens, and punctuation pass through untouched, so you stay in control of word and syllable boundaries. The output is rendered in the Charis SIL font, which displays every POJ mark correctly, so you can copy clean text straight into your documents.

Open the composer

Next steps