Devanagari Tha थ

Tha is the seventeenth consonant of the varnamala, the voiceless aspirated dental and the second member of the fourth varga. Its usual romanisation is a standing source of confusion in English, because the two letters used to write it spell, in English words, a single fricative sound that Sanskrit does not possess at all. The Sanskrit letter is a dental t with breath released after it, and it is neither the th of think nor the th of this. That mismatch is a property of the romanisation rather than of the script, and it is one of the reasons the scholarly transliteration systems mark aspiration and retroflexion with explicit diacritics rather than trusting a reader to interpret pairs of Latin letters correctly. The practical consequence shows up throughout English writing about the Indian traditions, where words containing this letter are routinely pronounced by English speakers in a way that has no relation to the Sanskrit sound. The atlas transliterates letter names in a consistent scheme and states the articulation in words alongside it, so that a reader who does not know the conventions is not left to guess from the spelling.

Devanagari itself carries no such ambiguity. Each of the two features the letter combines has its own consequence in the table, there is exactly one sign for the sound, and a reader of the script is never in doubt about which letter is meant. The ambiguity is created entirely by writing an Indian language in a Latin alphabet that has no places for the features the varnamala is built on.

A transliteration of Devanagari has to represent thirty-three consonants and fourteen vowels using an alphabet with twenty-six letters, and it has to do so reversibly if scholars are to cite texts precisely. Every serious system solves the problem the same way, by adding diacritics that stand for the features the table is built on: a dot beneath a letter for retroflexion, an acute or a dot for the sibilants, a macron for vowel length, and a following h for aspiration. Once the features are marked, the mapping is one to one and a reader who knows the system can write the Devanagari back out from the Latin.

Systems that avoid diacritics, which are common in popular publishing and in the spelling of names, cannot do that: they merge the three sibilants, lose vowel length, and produce letter pairs that English readers pronounce as English. Both kinds of spelling are in circulation for most of the words this atlas covers, which is why the same term appears in several forms in the general literature. Nothing in this is a fact about the letter itself, whose value is the voiceless aspirated dental and whose place is second in the fourth class, but it is the main practical difficulty a reader meets when moving between English sources and the script, and it is worth stating plainly.