The spelling of the word "Innga" can be explained using the International Phonetic Alphabet (IPA). The first letter "I" is pronounced as /ɪ/, which is a short and relaxed vowel sound. The second letter "n" is pronounced as /ŋ/, which is a nasal consonant sound similar to the "ng" sound in "sing". The third and fourth letters "g" are pronounced as /g/, which is a voiced velar plosive sound. Lastly, the fifth letter "a" is pronounced as /ə/, which is a neutral and unstressed vowel sound.