Welsh orthography: alphabet, spelling rules and diacritics

The alphabet and digraphs

The contemporary Welsh alphabet traditionally comprises 28 units, including eight digraphs that are treated historically as single letters for purposes such as collation. The conventional sequence is: a, b, c, ch, d, dd, e, f, ff, g, ng, h, i, (j), l, ll, m, n, o, p, ph, r, rh, s, t, th, u, w, y. The letter j has become common in modern lists because of its use in loanwords from English and other languages; inclusion is now generally accepted though some traditional lists omit it. In traditional collation the digraphs ch, dd, ff, ng, ll, ph, rh and th occupy single places in the alphabetic order, a feature sometimes handled differently by modern computer systems.

Spelling conventions and notable letters

Welsh treats w and y as vowels in addition to the five classic vowel letters a, e, i, o, u. Their values vary by position and dialect — for example, w often represents a close back vowel similar to English "oo". Consonant letters include several that represent sounds uncommon in English orthography, such as ll, a voiceless lateral fricative, and ng as a velar nasal. Because the orthography links spelling closely to phonology, learners quickly benefit from predictable letter–sound correspondences.

History and orthographic change

Modern Welsh spelling developed in the early modern period as printers and scholars sought a consistent system for religious, educational and legal texts. Decisions made in the 16th century influenced which letters remained in common use; for example certain letters fell out of regular printing usage and others were adapted to represent native sounds. Debates over the inclusion of particular letters and the handling of loanwords continued into later centuries, and orthographic reform and standardization have been gradual. Historical documents such as early translations of the New Testament and subsequent dictionaries played a central role in standardizing forms now seen in modern Welsh.

Diacritics and pronunciation marks

The most visible diacritic in Welsh is the circumflex, commonly used to indicate a lengthened vowel in a word; linguists and language learners often associate it with a long vowel quality. Other diacritic marks, such as the acute, grave or diaeresis, appear less frequently and tend to serve specialist or lexical purposes: for example, to mark stress, to distinguish homographs, or to show that two adjacent vowels should be pronounced separately rather than as a diphthong.

Practical use and distinctions

Welsh orthography interfaces with grammar through features such as initial consonant mutation, where the first consonant of a word changes in predictable ways in different grammatical contexts; these changes are written as standard letters and are an integral part of how words are spelled in sentences. The orthography is used in education, signage, media and computing; modern keyboards and software increasingly support Welsh-specific characters and collation rules, though legacy limitations sometimes affect ordering of digraphs. Understanding the alphabet, digraphs and diacritics is central to literacy in Welsh and to accurate representation of names, place-names and technical vocabulary.

• Alphabet and digraphs: ch, dd, ff, ng, ll, ph, rh, th.
• Vowels include: a, e, i, o, u, w, y — with w and y functioning as vowels.
• Common diacritic: circumflex (marks long vowel).
• Loanwords from English and other languages bring in forms using loanwords orthography conventions.

Further reading and resources on spelling rules, pronunciation charts and historical texts are available from language authorities and educational bodies that document the development and practical application of Welsh orthography.

More about the Welsh language • Loanword handling • English influence • Historical texts • Diacritics overview • Circumflex details • Vowel length and quality