There is a large body of literature on both the phonetic and phonological analyses of Thai tones, beginning in the early 20^th century (Bradley 1909 and 1911, Jones 1918 as quoted in Henderson 1976) that continues to today (Morén and Zsiga 2006, Zsiga 2007).  While the early works of Bradley and Jones did not specify the age and origin of the speakers recorded, recent ones have been careful to control for such facts as Thai has tonal dialectal variation.  Scholars generally agree that Thai tones are phonologically quite stable and no paradigmatic change has been proposed since the Great Tone Shift (Brown 1975, Li 1977, Gedney 1989).  The phonetic realization of the tones, however, seems to show some changes, particularly with younger speakers.  This study aims to provide a phonetic description of Bangkok Thai tones in three different age groups of native Bangkok Thai (BT henceforth) speakers: younger (under 25), middle age (30-40), and older speakers (50+).    

Some descriptions of Thai tones have tried to capture the tonal differences between younger and older speakers (Panroj 1991, Kantong 2008).  Most studies ignore the possibility, treating the tones as static across time and different speakers.  Abramson’s (1962) description, while nearly half a century old, is still widely cited by linguists and Thai language teachers alike as the norm for BT speech.  More recently, scholars such as Hoonchamlong (2007) are recognizing the tonal differences, albeit impressionistically, between older and younger speakers.  Morén and Zsiga (2006), for example, show a vastly different tonal contour than those recorded by Abramson (1962).  The data, unfortunately, was from only two speakers.

            The goal of the study is two-pronged.  First, the study aims to describe, phonetically, the citation form pronunciation of native young (below 25), middle age (30-40), and older speakers (50+) of BT.  Second, the study compares the tones of each age group in search of generational markers in the tonal system.  Fifteen speakers (five per age group) were recorded reading twenty-five words (five words per tone and per each place of articulation) in identically framed sentences.  The F0 measurements are normalized and averaged to illustrate the tonal contours for each age group.  An accurate and current phonetic description of BT has great academic and pedagogical value for both linguists and Thai language teachers.