古入声字按古声母的清浊分化为甲、乙两个调类的方言,一般是古清声母字归甲类,古全浊声母字归乙类。古入声次浊声母字不稳定,有一部分古次浊声母字跟甲类走,归甲类,另一部分跟乙类走,归乙类。许多方言都是这样,包括客家方言和其他方言。但是在客家方言里,古入声次浊声母字哪些字跟古清声母入声字走,归甲类,哪些跟古全浊声母入声字走,归乙类,似乎有一定的规律。黄雪贞先生《客家方言声调的特点》和《客家方言声调的特点续论》讨论了十八处客家方言古入声次浊声母字的分化问题,这十八处方言是广东的梅县、兴宁、大埔、蕉岭、平远、丰顺、惠阳、陆丰、紫金;福建的永定、长汀;广西的陆川、贺县;湖南的酃县;台湾的桃园、美浓;四川成都的龙潭寺;还有一处未说明确切地点的广东客家方言,见于 D.Maciver 编, Ancient into the voice of the voiced by the ancient voiced voiced differentiation into A, B two tone dialect, usually the ancient Qing initials into a class, the ancient turbid initials to B class. The voiced sound of the ancient reverberation is unstable, and some of the ancient voiced consonants follow the Class A, which are classified as Class A and the other part of Class B with Class B. This is true in many dialects, including Hakka dialects and other dialects. However, in the Hakka dialect, the ancient reverberation of voiced alphabetical characters which words followed the ancient Qing initials into acoustical, which with the ancient voiced initials into sound, go to class B, there seems to be a certain law. Huang Xuezhen “Hakka dialect tone features” and “Hakka dialect tone characteristics of the continued discussion” Hakka dialect eighteen Hakka dialect ancient times voiced the voiced consonants of the differentiation of these 18 dialects is the Guangdong Meixian Xingning, Taiyuan, Jiaoling, Pingyuan, Fengshun, Huiyang, Lufeng and Zijin; Yongding and Changting in Fujian; Luchuan and Hexian in Guangxi; Lixian County in Hunan; Taoyuan and Mino in Taiwan; Longtan Temple in Chengdu, There is a Cantonese Hakka dialect that does not state the exact location, found in D. Maciver,