Submitted on: 25 July 1999.
Revised on: 23 August 1999.
Accepted on: 10 September 1999.
Language Variation and Change---CAMBRIDGE UNIV PRESS
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http://reply.papertrans.cn/3/207/20639/20639-13.png
Submitted on: 21 October 2012.
Revised on: 21 November 2012.
Accepted on: 30 November 2012.
Language Variation and Change---CAMBRIDGE UNIV PRESS
http://reply.papertrans.cn/3/207/20639/20639-15.png
http://reply.papertrans.cn/3/207/20639/20639-16.png
http://reply.papertrans.cn/3/207/20639/20639-17.png
http://reply.papertrans.cn/3/207/20639/20639-18.png
Submitted on: 20 February 2003.
Revised on: 23 March 2003.
Accepted on: 08 April 2003.
Language Variation and Change---CAMBRIDGE UNIV PRESS
Submitted on: 20 January 2014.
Revised on: 11 February 2014.
Accepted on: 08 March 2014.
Language Variation and Change