This volume comprises the first comprehensive grammar of a language from the Aslian subgroup, within the Mon-Khmer branch of the Austroasiatic family. Spoken by approximately 4,000 people in the lowland forests of theMalay Peninsula, Semelai has many distinctive features of interest to linguistic typologists, phonologists, morphologists and syntacticians. The volume provides a unique reference resource for South-East Asian language specialists, as well as general linguists.ErratumTo follow the final paragraph of Section 1.3.2, p21.Hoe Ban Sengâ's 1964 undergraduate field report, published in 2001, devoted a chapter to a preliminary presentation of the Semelai language (Hoe2001:95-124) recording an extensive vocabulary of approximately 900 items, and samples of the language with Malay and English glosses. The Malay-based orthography had limitations, failing for example to distinguish the full inventory of vowels, and voiceless aspirated stops, although managing to capture the distinction between the final voiceless velar and glottal stops.Giannoâ's dissertation, published as Gianno (1990) advanced upon Hoe in accuracy by presenting linguistic data in a phonemic orthography based on work by Gerard Diffloth. It includes narrative transcriptions and appendices devoted to lists of Semelai plant names and related terminology all based on that phonemicisation. The Gianno/Diffloth phonemicisation, to which I only gained access after completing my own initial phonological analysis, is broadly similar to the one advanced here, in recognising ten oral vowels, each with a phonemically nasal counterpart, and three series of stops: voiced, voiceless and voiceless aspirated. It also differs from it in a number of significant points, including an absence of a series of pre-glottalised sonorants and voiceless nasals, the inclusion of a voiced velar fricative, and the treatment of nasality on vowels.