A Glottocode is the unique, persistent identifier that Glottolog gives to each language, dialect or family. It is four letters or digits followed by four digits, such as wels1247 for Welsh. It lets data about the same language be joined reliably.
Key takeaways
- A Glottocode is an eight-character identifier: four lowercase letters or digits, then four digits.
- Every language, dialect and family in Glottolog has its own, and it stays the same over time.
- Welsh is wels1247 and Basque is basq1248.
- Our map uses Glottocodes to join areas, speaker figures and classification for the same language.
How Glottocodes work
Each entry in Glottolog has a unique and persistent identifier called a Glottocode. It consists of four alphanumeric characters, meaning lowercase letters or decimal digits, and then four decimal digits [1]. The pattern is fixed, but the letters are usually a hint at the name, which is why a code can often be recognised at a glance.
The point of a code is to give each language one name that does not change. Language names are slippery: the same language can go by several names in English and other names in its own community, and one name can be used for different varieties. An identifier avoids that. It is meant to refer to exactly one entry, and to stay the same for as long as the entry exists [1].
Glottocodes are assigned not only to languages but to every languoid: families, languages and dialects [2]. That makes them useful for joining data from different projects. A dictionary project, a map and a survey of speakers can all store the same Glottocode, and software can then match them without relying on spelling.
The codes are separate from ISO 639-3 codes, which are three letters long and cover languages rather than families or dialects. Many datasets carry both.
An example from our data
Every language page on the map shows its Glottocode. Welsh is wels1247, with the ISO code cym. Basque is basq1248 (eus), Yoruba is yoru1245 (yor) and Navajo is nava1243 (nav).
The map uses these codes behind the scenes. A language's traditional area comes from an atlas, its family and endangerment status come from Glottolog, and its speaker figure comes from another source. The Glottocode is the key that ties them together for each of the 6,722 languages shown. Where an atlas has no area for a language, the code still lets the map place it as a dot.
The thing people get wrong
A frequent assumption is that a code like wels1247 spells out the language, or that two codes with similar letters mean related languages. The letters are only a convenience, and they carry no information about family. Another is that the code is a rating of a variety as a language. It is not: dialects get Glottocodes too [2], so having one says nothing about whether a variety counts as a language.
Glottocode vs ISO 639-3 code
| Glottocode | ISO 639-3 code | |
|---|---|---|
| Length | Eight characters | Three letters |
| Example | wels1247 | cym |
| Covers | Families, languages and dialects | Mainly languages |
Frequently asked questions
How many characters is a Glottocode?
Eight: four lowercase letters or digits, then four decimal digits.
Is a Glottocode the same as an ISO code?
No. An ISO 639-3 code has three letters, while a Glottocode is longer and also covers families and dialects.
Where can I find a language's Glottocode?
On its page on this site, and on its entry at glottolog.org.
Sources
- Glottolog glossary, Glottolog.
- Glottolog, Max Planck Institute for Evolutionary Anthropology.
- Every figure from our own map is worked out from the datasets on the data sources page (checked against Glottolog and Glottography, retrieved 13 October 2026).