American English (AmE, AE, AmEng, USEng, en-US), sometimes called United States English or U.S. English, is the set of varieties of the English language native to the United States. American English is a particularly influential form of English worldwide. English is the most widely spoken language in the United States and is the de facto common language used by the federal and state governments, to the extent that all laws and compulsory education presume English as the primary language. English is explicitly given official status by 32 of the 50 state governments. While the local courts in some divisions of the United States grant equivalent status to both English and another language—for example, English and Spanish in Puerto Rico—under federal law, English is still the official language for any matters being referred to the United States district court for the territory. The use of English in the United States is a result of British colonization of the Americas. The first wave of English-speaking settlers arrived in North America during the 17th century, followed by further migrations in the 18th and 19th centuries. During the 17th century, dialects from many different regions of England existed in every American colony, allowing a process of extensive dialect mixture and levelling in which English varieties across the colonies became more homogeneous compared with varieties in England. English thus predominated in the colonies even by the end of the 17th century's first massive immigrations of non-English speakers from Europe and Africa, and firsthand descriptions of a fairly uniform American English became common after the mid-18th century. Since then, American English has developed into some new varieties, including regional dialects that, in some cases, show minor influences in the last two centuries from successive waves of immigrant speakers of diverse languages, primarily European languages. American English varieties include many patterns of pronunciation, vocabulary, grammar, and particularly spelling that are unified nationwide but distinct from other English dialects around the world. Any American or Canadian accent perceived as free of noticeably local, ethnic, or cultural markers is popularly called "General" or "Standard" American, a fairly uniform accent continuum native to certain regions of the U.S. and associated nationally with broadcast mass media and highly educated speech. However, historical and present linguistic evidence does not support the notion of there being one single "mainstream" American accent. The sound of American English continues to evolve, with some local accents disappearing, but several larger regional accents having emerged in the 20th century.