authorities and in courts anywhere in the country. As a foreign language Vietnamese is increasingly being taught in schools and institutions outside of Vietnam, a large part which is contributed by its large diaspora. In countries with strongly established Vietnamese-speaking communities such as the United States, France, Australia, Canada, Germany, and the Czech Republic, Vietnamese language education largely serves as a cultural role to link descendants of Vietnamese immigrants to their ancestral culture. Meanwhile, in countries near Vietnam such as Cambodia, Laos, and Thailand, the increased role of Vietnamese in foreign language education is largely due to the recent recovery of the Vietnamese economy. Since the 1980s, Vietnamese language schools () have been established for youth in many Vietnamese-speaking communities around the world, notably in the United States. Similarly, since the late 1980s, the Vietnamese-German community has enlisted the support of city governments to bring Vietnamese into high school curriculum for the purpose of teaching and reminding Vietnamese German students of their mother-tongue. Furthermore, there has also been a number of Germans studying Vietnamese due to increased economic investments and business. Historic and stronger trade and diplomatic relations with Vietnam and a growing interest among the French Vietnamese population (one of France's most established non-European ethnic groups) of their ancestral culture have also led to an increasing number of institutions in France, including universities, to offer formal courses in the language. Phonology Vowels Vietnamese has a large number of vowels. Below is a vowel diagram of Vietnamese from Hanoi (including centering diphthongs): {| class="wikitable" style="text-align: center;" |- ! ! Front ! Central ! Back |- ! Centering | ia/iê | ưa/ươ | ua/uô |- ! Close | i/y | ư | u |- ! Close-mid/Mid | ê | ơ â | ô |- ! Open-mid/Open |e | a ă | o |} Front and central vowels (i, ê, e, ư, â, ơ, ă, a) are unrounded, whereas the back vowels (u, ô, o) are rounded. The vowels â and ă are pronounced very short, much shorter than the other vowels. Thus, ơ and â are basically pronounced the same except that ơ is of normal length while â is short – the same applies to the vowels long a and short ă . The centering diphthongs are formed with only the three high vowels (i, ư, u). They are generally spelled as ia, ưa, ua when they end a word