The word "tonnish" is spelled with the letter combination "nn," which can be confusing for those unfamiliar with English orthography. The IPA phonetic transcription for this word is /ˈtɒnɪʃ/, wherein the "o" is pronounced as "ɒ," the "n" is pronounced as "n," and the double "n" is pronounced with a slight nasalization. The "-ish" ending is pronounced as "ɪʃ." Overall, the spelling and pronunciation of "tonnish" demonstrate some of the complexities and idiosyncrasies of the English language.