Counting in Scottish Gaelic: Numbers 1 to 100 Explained

Numbers turn up in the first week of every Gaelic course, and they are also one of the first places learners get stuck. Scottish Gaelic carries two parallel counting systems, lenites after the words for one and two, and keeps a set of special words for counting people that English simply does not have. Once the pattern is clear, counting in Scottish Gaelic stops feeling arbitrary and starts feeling elegant.

This guide walks through both number systems, the lenition rules, the personal numerals for people, ordinals and dates, and the mistakes that keep learners sounding uncertain.

The two number systems in Scottish Gaelic

Gaelic inherited a vigesimal system, which counts in twenties, and it gained a decimal system, which counts in tens. Both are correct and both are in daily use.

The traditional vigesimal system survives in conversation about age, years, money, people, and in most traditional songs and stories. The decimal system is the one used in schools, in modern textbooks, in maths lessons, and increasingly in broadcast news. The safest approach for a learner is to recognise both and choose one for production.

There is a practical reason for the split. The vigesimal system builds larger numbers from twenties: forty is literally two twenties. The decimal system builds them from tens in a way that maps directly onto English and onto the way numbers appear on a page.

Numbers 1 to 10

Two details matter more than pronunciation at this stage. First, the numbers one and two change shape depending on whether they stand alone or in front of a noun. Second, when counting out loud, in phone numbers, or in songs, Gaelic puts a small particle in front of the number: a h-aon, a dhà, a trì, a ceithir. That “a” is the counting particle, and it is the reason a Gaelic speaker reading a phone number sounds so rhythmic.

The lenition rule after one and two

This is the rule that separates learners who sound careful from learners who sound fluent.

• aon lenites the following noun and keeps it singular: aon chat (one cat), aon bhalach (one boy), aon mhàthair (one mother).
• dà also lenites, and also keeps the noun singular: dà chat (two cats), dà bhalach (two boys). “dhà” is the standalone form of the same word.
• trì and above take the plain plural with no lenition: trì cait (three cats), ceithir balaich (four boys).

So the endings of the noun do not follow the English logic of one-then-many. In Gaelic, the first three numbers behave differently: one and two pull the noun into the singular and soften its first consonant, then three onwards pushes it into the plural.

This is exactly the kind of pattern that responds well to spaced repetition, because it is a rule with exceptions that become automatic only after repeated exposure. The beginner’s guide to Scottish Gaelic with spaced repetition explains how to build that habit systematically, and the essentials of Scottish Gaelic grammar cover the wider mutation system behind it.

Numbers 11 to 19

The teens are formed by placing deug after the unit:

• 11 aon deug
• 12 dhà dheug
• 13 trì deug
• 14 ceithir deug
• 15 còig deug
• 16 sia deug
• 17 seachd deug
• 18 ochd deug
• 19 naoi deug

Notice that deug, like every other noun after one and two, is affected by what comes before it: aon deug stays plain, but dhà dheug shows the lenited form. If the pronunciation of deug feels hard, the guide to the sounds beginners struggle with covers the broad and slender consonant pairs that cause most of the difficulty.

Tens, twenties, thirties: 20 to 90

Here the two systems visibly diverge.

The traditional column is the one that still appears in everyday speech in the Highlands and Islands, particularly for ages and for money. A speaker who says tha mi ceithir fichead is saying “I am eighty”. A speaker using the decimal system says ceithir fichead too, so twenty and eighty are the two places where a learner can hesitate.

Building 21 to 99

The connective that does the work here is ‘s a, short for agus a, meaning “and the”. Numbers between the tens are built with it:

• 21 fichead ‘s a h-aon
• 22 fichead ‘s a dhà
• 23 fichead ‘s a trì
• 29 fichead ‘s a naoi

The same structure repeats across the traditional tens: dà fhichead ‘s a còig is 45, trì fichead ‘s a seachd is 67. In the decimal system the logic is identical, only the base changes: trichead ‘s a h-aon is 31, caogad ‘s a dhà is 52.

One hundred and beyond

Ceud is one hundred. Dà cheud is two hundred, and the lenition after dà is visible. Ceud ‘s a h-aon is one hundred and one, dà cheud ‘s a h-aon is two hundred and one, and mìle is a thousand.

Large numbers are where Gaelic and English part company most sharply, because the vigesimal system continues in twenties rather than switching to hundreds at a hundred and one. Traditional speakers will happily say còig fichead for one hundred, “five twenties”. This is not slang or poetry. It is ordinary arithmetic in a language that counted in twenties for centuries.

Counting people: the personal numerals

Gaelic keeps separate words for counting human beings, and they are used constantly. Aon duine is one person, but from two onwards the number changes form:

These are nouns in their own right, so they take a following noun in the genitive plural: triùir bhalach is three boys, ceathrar chaileagan is four girls, dithis mhac is two sons. Above ten, the pattern breaks back into ordinary numbers: aon duine deug is eleven people.

These personal numerals are used in the same contexts as English “a couple”, “a trio”, and “a group of five”: còigear air an rathad, five people on the road. Place names and landscape words often sit alongside them in everyday Highland speech, and the guide to Scottish place names shows how the same grammatical machinery appears in names you already know.

Ordinal numbers and dates

Ordinals behave differently from cardinals:

• a’ chiad (first)
• an dàrna (second)
• an treas (third)
• an ceathramh (fourth)
• a’ chòigeamh (fifth)
• an siathamh (sixth)

Only first is irregular in a way that surprises learners: it is a’ chiad, never aonamh. Dates use the ordinal for the day: a’ chiad latha dhen Fhaoilleach, the first day of January.

Common mistakes to avoid

• Saying dhà chat instead of dà chat before a noun. Standalone counting uses dhà, noun phrases use dà.
• Using a plural noun after dà: dà cait is wrong, dà chat is right.
• Forgetting lenition after aon and dà, which makes phrases like aon cat sound unfinished to a native ear.
• Mixing systems inside one sentence, for example trichead ‘s a còig fichead.
• Avoiding the personal numerals and saying dà duine for two people, which is understandable but marks a learner immediately.

How to make numbers stick

Numbers are a closed set with high frequency, which makes them ideal for spaced repetition. Learn ten at a time, then use them in real contexts rather than reciting them.

• Count objects you actually handle: steps, eggs, sachets of coffee, windows in a building.
• Read ages and years aloud from any Gaelic news article.
• Use the counting particle in phone numbers until it feels natural.
• Listen to BBC Alba and Radio nan Gàidheal programmes about numbers, prices and sport, where numerals appear constantly.
• Check the everyday Gaelic phrases for beginners once you can count, because greetings, times and prices all depend on numbers.