The spelling of the word "Jianni" can be explained with the use of IPA phonetic transcription. The first two letters "Ji" represent a voiced palatal fricative sound /ʒi:/, followed by the letter "a" which is pronounced as a low central vowel /æ/. The last two letters "nni" represent a double consonant /n/ and a short i sound /i/. Therefore, the correct spelling of "Jianni" would be /ʒi:æni/. It is important to use proper phonetic transcription to accurately represent the pronunciation of words.