Does Cardiff Have the Most Welsh Speakers? Census and APS Explained

Does Cardiff have the most Welsh speakers in Wales? The honest answer is: it depends which official dataset you mean. The Annual Population Survey for the year ending December 2025 estimates that Cardiff had the highest number among Welsh local authorities, at 96,800. Census 2021 counted 42,757 Welsh speakers in Cardiff, placing it third behind Gwynedd and Carmarthenshire.

Those figures are not interchangeable scoreboards. One comes from a sample survey and one from a census. They answer similar-looking questions with different methods, dates and levels of uncertainty. A strong headline names the source before declaring a winner.

Does Cardiff have the most Welsh speakers? Two answers

Cardiff Council’s 2025-26 Welsh Language Standards Annual Report gives the APS estimate and calls it the highest absolute local-authority estimate in Wales. The Welsh Language Commissioner’s Census 2021 summary lists Gwynedd at about 73,600 Welsh speakers, Carmarthenshire at about 72,800 and Cardiff at exactly 42,757.

Both statements can therefore be accurately reported. Trouble begins when “APS estimate” or “Census count” is removed and the number is presented as a timeless fact.

Why are the APS and census figures so different?

The Annual Population Survey is a sample survey. Its local-authority numbers are estimates derived from the people sampled and then weighted to represent the wider population. The census aims to count the whole usual-resident population at a particular point in time. Sampling, weighting, response patterns, question context and the four-year date gap can all affect the result.

StatsWales adds an important warning. Accreditation of APS estimates has been suspended following changes including lower sample sizes and reweighting, and uncertainty is higher for local-authority results. It identifies the census as the key source for Welsh-language ability, especially when comparing smaller areas.

“Most Welsh speakers” can mean number or percentage

Cardiff is Wales’s largest city, so it can have a large number of Welsh speakers without having the highest proportion. These are different questions:

• Absolute number: How many people report that they can speak Welsh?
• Percentage: What share of the local population reports that ability?

For planning a city-wide service, the number may matter: thousands of potential Welsh-speaking users are present. For understanding how dominant Welsh is in everyday local life, percentage and patterns of use may tell more. Neither measure alone shows how often people speak Welsh, their confidence, where they use it or whether they can access services through it.

The Welsh word for Cardiff is Caerdydd, and Welsh is Cymraeg. Seeing those words on transport, schools, workplaces and cultural venues is visible evidence of language policy and community life, but visibility should not be mistaken for a population estimate either.

What has changed in Cardiff?

Census data show a long rise in Cardiff’s Welsh-speaking count: Cardiff Council records 18,071 in 1991 and 42,757 in 2021. Between 2011 and 2021, the proportion rose from 11.1% to 12.2%, and the number increased by just over 6,000. The Office for National Statistics described Cardiff’s 1.1 percentage-point rise as the largest percentage-point increase among Welsh local authorities in that census period.

The APS series gives a more recent, higher picture. Cardiff Council reports an increase from an estimated 86,400 people, or 23.8%, in the year ending June 2023 to 96,800, or 26.4%, in the year ending December 2025. Because the APS is a survey and local estimates carry higher uncertainty, the movement should not be narrated as if every change were a precise headcount.

A useful interpretation is directional and cautious: multiple official sources point to a substantial Welsh-speaking population in Cardiff, while the precise size depends heavily on the dataset. That supports investment in opportunities to learn and use Welsh without pretending the statistical question is settled by one number.

How to cite the Cardiff Welsh-speaker claim accurately

Use the shortest sentence that keeps the method and date:

When space allows, add the percentage and a link to the source. When making a chart, do not place the APS and census values in one continuous line unless the chart clearly marks the break in method. A smooth graphic can create a false sense of comparability.

This discipline matters beyond statistics. Organisations planning Welsh-language services need to know whether they are using a robust baseline, a recent indicator or evidence of actual language use. Read bilingualism in business for the practical case, and use ten easy Welsh words for beginners to turn interest into a first action.

So, is Cardiff number one?

Say “yes” only with the APS label attached. Say “no, third” only with the Census 2021 label attached. If you do not have room to name a source and date, the ranking is probably too fragile for the format.

The more durable conclusion is more interesting than the contest: Cardiff has one of the largest Welsh-speaking populations in Wales, and its role looks different when measured by headcount, proportion, ability or daily use. Good statistical writing keeps those dimensions visible.