This new book by Marianne Celce-Murcia and Elite Olshtain offers valuable information and pedagogical suggestions for any language teacher or trainer of teachers. The focus is on the role of discourse in language teaching: how to prepare learners for communicative interaction (written and spoken) by exposure to authentic language use and a focus on "the social and cultural environment within which communicative language processing and interaction take place" (p.

Cross-linguistically, fricatives are the rarest types of rhotics, found in a few African and European languages (Ladefoged & Maddieson 1996) and as allophones in some Romance languages (Jesus & Shadle 2005; Recasens 2002; Bradley 2006; Colantoni 2006). Acoustic data from Nusu, phonotactic reasoning, and a cognate comparison demonstrate the presence of alveolar fricative rhotics in Tibeto-Burman. The Nusu rhotic appears in syllable-initial position as the first or second consonant and can be realized as alveolar approximants [ɹ] or [ɹʲ], non-sibilant voiced and voiceless fricatives [ɹ̝, ɹ̥], as well as voiced sibilant [ʐ]. In other studies on Nusu, these fricative rhotics have sometimes been reported as retroflex voiced sibilants (Sun & Lu 1986; Fu 1991), but intra-speaker and cross-variety comparison point to classification as rhotics. Evidence from other Tibeto-Burman languages suggests that alveolar fricative rhotics are not limited to Nusu. Together these data challenge the tradition of generally interpreting alveolar fricatives as sibilants.