Other Kra–Dai languages are transcribed with analogous conventions. The following table of the phonetic characteristics of Proto-Tai tones was adapted from Pittayaporn.: 271 Note that *B and *D are phonetically similar. Proto-Tai tones take on various tone values and contours in modern Tai languages. These tonal splits are determined by the following conditions:  In addition, William J. Gedney developed a "tone-box" method to help determine historical tonal splits and mergers in modern Tai languages. There is a total of 20 possible slots in what is known as the Gedney's Tone Box. Proto-Tai tones correspond regularly to Middle Chinese tones. (Note that Old Chinese did not have tones.) The following tonal correspondences are from Luo (2008). Note that Proto-Tai tone *B corresponds to Middle Chinese tone C, and vice versa. Gedney (1972) also included a list of diagnostic words to determine tonal values, splits, and mergers for particular Tai languages. At least three diagnostic words are needed for each cell of the Gedney Box. The diagnostic words preceding the semicolons are from Gedney (1972), and the ones following the semicolons are from Somsonge (2012) and Jackson, "et al." (2012). Standard Thai (Siamese) words are given below, with "italicised" transliterations. Note that the diagnostic words listed above cannot all be used for other Tai-Kadai branches such as Kam–Sui, since tones in other branches may differ. The table below illustrates these differences among Tai and Kam–Sui etyma. In 2007, Peter K. Norquest undertook a preliminary reconstruction of Proto-Southern Kra-Dai, which is ancestral to the Hlai languages, Ong Be language, and Tai languages. There are 28 consonants, 5-7 vowels, 9 closed rimes (not including vowel length), and at least 1 diphthong, *ɯa(C). Proto-Southern Kra-Dai medial consonants also include:   Proto-Southern Kra-Dai also includes the diphthong *ɯa(C). Unlike its modern-day monosyllabic descendants, Proto-Tai was a sesquisyllabic language (Pittayaporn 2009). Below are some possible Proto-Tai syllable shapes from Pittayaporn.: 64  "Legend":  During the evolution from Proto-Tai to modern Tai languages, monosyllabification involved a series of five steps.: