This book marks a new development in the field of grammaticalisation studies, in that it extends the field of grammaticalisation studies from relatively homogeneous languages to those possessing well-established and institutionalised second language varieties. In Hypothetical Modality, special reference is made to Singaporean English, a native-speaker L2 dialect of considerable importance in the South-East Asian region, and to the expression in the dialect of hypothetical modality, which appears to be indistinguishable from non-hypothetical modality in terms of the use of preterite or past forms of modal verbs. Within a grammaticalisation
framework, a number of factors can be seen to be relevant to an explanation, including substratum and contact features such as tense/aspect marking, levels of lexical retention as an individual (psychological) phenomenon, and the fact that such dialects have a discontinuity in their development. In addition, the book defines pragmatic approaches to the understanding of hypothetical modality, in both diachronic and synchronic terms.

Lionel Wee, Singapore in English World-Wide 22:2, 2001:
Debra Ziegeler's book makes a valuable contribution by bringing together two areas of research which are, more often then not, treated seperately: the development of grammar in contact sitautions and the study of grammaticalisation. The book is to be recommended for bridging grammaticalisation and contact studies. It also has much to offer to anyone specifically interested in the phenomenon of hypothetical modality.