Traditionally Māori were reluctant to reveal their tribal knowledge to Europeans for fear of being mocked or considered barbaric, and also a belief in keeping tribal secrets. When Kingitanga allowed Michael King to write the biography of "Princess" Te Puea, because of his sensitivity to Māori, they still withheld material that would not show her in a good light. Both Māori and Pākehā have borrowed cultural forms and styles from other countries, particularly Britain and the United States. Most popular New Zealand music derives from Anglo-American styles, particularly rock music, hip-hop, electronic dance music and related subgenres. Although there is evidence of a "New Zealand style", many groups incorporate New Zealand themes into their work, so this style affects each "genre" differently. Since the 2000s, Dubstep, Drum and Bass, Jungle Trance and related subgenres, derived from England, has been further developed by New Zealanders into a unique sound, exemplified by Salmonella Dub, Shapeshifter and many others. The visual arts have also shown the influence of international movements, for example cubism in the early work of Colin McCahon. In general, the development of international mass media and mass communication has meant New Zealanders have always been aware of developments in other countries; this lends itself to the adoption of new forms and styles from overseas. New Zealand has three official languages. English is the primary official language with its use unrestricted anywhere. The Māori language and New Zealand Sign Language also have official status, in certain contexts, as defined by their respective statutes. Other languages are also spoken in New Zealand by some immigrant communities. New Zealand English is close to Australian English in pronunciation, but has several differences often overlooked by people from outside these countries. The most prominent differences between the New Zealand English dialect and other English dialects are the shifts in the short front vowels: the short-"i" sound (as in "kit") has centralised towards the schwa sound (the "a" in "comma" and "about"); the short-"e" sound (as in "dress") has moved towards the short-"i" sound; and the short-"a" sound (as in "trap") has moved to the short-"e" sound. Some of these differences show New Zealand English to have more affinity with the English of southern England than Australian English does. Several of the differences also show the influence of Māori speech. The New Zealand accent also has some Scottish and Irish influences from the large number of settlers from those places during the 19th century.