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Release Date: 9/17/2026
Format: MP3
Size: 4.40 MB
A collection of spontaneous responses to questions in Welsh (Cymraeg).
Restrictions/Special Constraints
None provided.
Forbidden Usage
It is forbidden to attempt to determine the identity of speakers in the Common Voice datasets. It is forbidden to re-host or re-share this dataset.
Intended Use
This dataset is intended to be used for training and evaluating automatic speech recognition (ASR) models. It may also be used for applications relating to computer-aided language learning (CALL) and language or heritage revitalisation.
cy)This datasheet is for sps-corpus-5.0-2026-09-11 of the Mozilla Common Voice Spontaneous Speech dataset for Welsh [Cymraeg - cy]. The dataset contains 17 clips representing 0.21 hours of recorded speech (0 hours validated) from 4 speakers.
The Welsh language (Cymraeg - /kəmˈraːiɡ/) belongs to the Celtic language family, specifically the Brythonic branch of Insular Celtic. Welsh evolved in the 6th century, alongside Breton and Cornish, from Common Brittonic, the common language previously spoken throughout Great Britain during the Iron Age and Roman period. The language has experienced contact with English since medieval times, leading to extensive lexical borrowing and gradual language shift intensified by socioeconomic factors and educational policies. It's resilience however stems from concentrated communities, intergenerational transmission, cultural traditions like the Eisteddfod, and religious revival movements. Strategic activism by speakers from the 1960s onwards has transformed Welsh from a declining minority language into one with official legal status. The most recent census shows 538,300 speakers (17.8% of Wales' population), though other surveys suggest higher figures of up to 862,700 speakers. Legislation by the Senedd (Welsh Parliament) supports revitalization through education and technology, with the goal of achieving one million speakers and doubled daily usage by 2050.
Welsh language speech varies significantly across proficiency levels (from native speakers and learners to passive understanders), regional dialects (mainly northern and southern, plus Patagonian Welsh), and registers (formal literary Welsh versus more informal colloquial spoken forms that sometimes incorporates code-switching). Speaker competence ranges widely, with some demonstrating full fluency across all domains while others show more limited or context-specific abilities.
The dataset clips are categorised by transcription status and training-set assignment. The following tables summarise the distribution.
| Bucket | Clips | % |
|---|---|---|
| Transcribed & Validated | 3 | 17.6% |
| Transcribed & Pending | 0 | 0.0% |
| Not transcribed | 14 | 82.4% |
| Bucket | Clips | % |
|---|---|---|
| Train | 0 | 0.0% |
| Dev | 0 | 0.0% |
| Test | 0 | 0.0% |
| Unassigned | 17 | 100.0% |
Training split coverage: 0 of 3 transcribed & validated clips (0.0%)
| Bucket | Clips | % |
|---|---|---|
| Validated | 3 | 100.0% |
| Pending | 0 | 0.0% |
| Edited | 0 | 0.0% |
Welsh employs a Latin alphabet of 29 letters, including eight digraphs (ch, dd, ff, ng, ll, ph, rh, th) treated as single letters for alphabetization, and treats "w" and "y" as vowels. The orthography is largely phonetic with predictable sound-letter correspondences. Loanwords, especially from English, are occasionally adapted to Welsh spelling conventions.
The 29 letters used for alphabetization in Welsh are:
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 is borrowed from English to represent the borrowed /dʒ/ consonant phoneme.
Welsh also uses diacritical marks on vowels (considered variants of their base letters, not separate letters for alphabetization):
With circumflex ('to bach'): â ê î ô û ŵ ŷ
With acute accent: á é í ó ú ẃ ý
With grave accent: à è ì ò ù ẁ ỳ
With diaeresis: ä ë ï ö ü ẅ ÿ
The traditional system lacks letters k, q, v, x, z, although these can appear in proper nouns and technical terms.
There follows a randomly selected sample of questions used in the corpus.
Beth wyt tiʼn hoffi ei wneud yn dy amser sbâr?
Beth wyt tiʼn hoffi ei wneud ar y penwythnos?
Wyt tiʼn hoffi coginio? Beth wyt tiʼn hoffi ei wneud?
Sut maeʼr tywydd yn effeithio ar dy hwyliau di?
Beth ywʼr peth gorau am fyw yng Nghymru?
There follows a randomly selected sample of transcribed responses from the corpus.
Dw i'n mwynhau sglodion
O'n i'n casau pys
Dw i'n hoffi gwrando ar gerddoriaeth Beethoven
Each row of a tsv file represents a single audio clip, and contains the following information:
client_id - hashed UUID of a given user
audio_id - numeric id for audio file
audio_file - audio file name
duration_ms - duration of audio in milliseconds
prompt_id - numeric id for prompt
prompt - question for user
transcription - transcription of the audio response
votes - number of people that who approved a given transcript
age - age of the speaker1
gender - gender of the speaker1
language - language name
split - for data modelling, which subset of the data does this clip pertain to
char_per_sec - how many characters of transcription per second of audio
quality_tags - some automated assessment of the transcription--audio pair, separated by |
transcription-length - character per second under 3 characters per second
speech-rate - characters per second over 30 characters per second
short-audio - audio length under 2 seconds
long-audio - audio length over 5 minutes
non-allowed-script - transcription contains characters from a writing system not associated with the language
mixed-script-words - a single word contains characters from multiple writing systems
mixed-script-transcription - transcription spans multiple writing systems, but each word consistently uses only one
Dewi Bryn Jones (https://github.com/DewiBrynJones)
Gareth Watkins (https://github.com/grw20blt)
This dataset is released under the Creative Commons Zero (CC-0) licence. By downloading this data you agree to not determine the identity of speakers in the dataset.
For a full list of age, gender, and accent options, see the demographics spec. These will only be reported if the speaker opted in to provide that information. ↩ ↩2