English has eventually become the leading language of international discourse in the 21st century. English has developed over the course of more than 1,400 years. Modern English has been spreading around the world since the 17th century by the worldwide influence of the British Empire and the United States. Through all types of printed and electronic media of these countries, English has become the leading language of international discourse and the lingua franca in many regions and professional contexts such as science, navigation and law. Modern English grammar is the result of a gradual change from a typical Indo-European dependent marking pattern, with a rich inflectional morphology and relatively free word order, to a mostly analytic pattern with little inflection, a fairly fixed subject–verb–object word order and a complex syntax. Modern English relies more on auxiliary verbs and word order for the expression of complex tenses, aspect and mood, as well as passive constructions, interrogatives and some negation. English is the largest language by number of speakers, and the third most-spoken native language in the world, after Standard Chinese and Spanish. It is the most widely learned second language and is either the official language or one of the official languages in almost 60 sovereign states. There are more people who have learned it as a second language than there are native speakers. As of 2005, it was estimated that there were over 2 billion speakers of English. English is the majority native language in the United States, the United Kingdom, Canada, Australia, New Zealand and Ireland, an official and the main language of Singapore, and it is widely spoken in some areas of the Caribbean, Africa, South Asia, Southeast Asia, and Oceania. It is a co-official language of the United Nations, the European Union and many other world and regional international organizations. It is the most widely spoken Germanic language, accounting for at least 70% of speakers of this Indo-European branch. English speakers are called “Anglophones”. Variability among the accents and dialects of English used in different countries and regions—in terms of phonetics and phonology, and sometimes also vocabulary, idioms, grammar, and spelling—does not typically prevent understanding by speakers of other dialects, although mutual unintelligibility can occur at extreme ends of the dialect continuum.