Only five fully nation-states do not currently have a de jure or official primary language:
- UK see here
- USA, though 32 states now at least one official language — see here
- Australia: Over 80% of people speak English, but there is no official national language.
- Eritrea: Tigrinya, Arabic, and English are the working languages.
- Mexico: Spanish is spoken by the vast majority, but is not the official language. This is aimed at protecting minority languages.
Arguably, Argentina could be added to this list. Spanish is the language used in all official interactions, but it has not been legally declared the official language.
Why these countries?
Three of these four countries are from the anglosphere - countries with majority English-speaking populations. A short explanation as to why this has influenced the official language question here:
An extended version of this piece is on Medium (3-min free read)