The spelling of the word "Tiah" can be explained using the International Phonetic Alphabet (IPA). The first sound is the "t" sound (/t/), which is an unvoiced alveolar plosive. The second sound is the "i" sound (/i/), which is a close front unrounded vowel. The third sound is the "a" sound (/ə/), which is a schwa sound. The final sound is the "h" sound (/h/), which is an unvoiced glottal fricative. Therefore, the correct spelling of this word is "Tiah" (/tiaəh/).