When a language is declared to be national, the state isn't committing to use that language itself, but rather to protect and promote it so that citizens can use it more readily. Thus, governments can opt for "national status" because it seems less binding than "official status," which forces them to actually use the language in question.
What's more, the approach recognizes that the linguistic group forms part of the country's national heritage, and thus represents more than a simple minority. In principle, all of the languages spoken by a country's inhabitants could qualify as national languages. But recognizing a language in a legal document carries major implications, because that recognition automatically bestows rights.
In Switzerland, for example, the three official federal languages are German, French and Italian, but the country's national languages are German, French, Italian and Romansh; thus, national languages can also be official languages. In Switzerland, Romansh-speaking citizens have acquired certain rights, but not as many as those granted to speakers of the three other languages.
In the United Kingdom, the official language is English, but Gaelic in Wales, Scottish in Scotland and Irish in Ireland are "national languages." In other words, a national language isn't necessarily an official language. In African countries such as Senegal, the government promotes instruction in Wolof as a national language, but continues to use French as the administration's officiallanguage. Zimbabwe takes the same approach with Shona in the area of education and justice, while relying on English in all other sectors. So, national-language status is lower than official-language status, but it still provides protection and promotion on behalf of the state.
In Canada, the two official languages-English and French-are also national languages, but the term carries no legal weight under Canada's current structure. The languages of Canada's Native Peoples could also qualify as national languages, but for various reasons, the country does not use the concept of national languages in its legislation.