The spelling of the word "Tunison" can be a bit confusing because of the silent "i". It is pronounced as /tuːnɪsən/ and not as "toon-ison". The "u" is pronounced as "oo", while the "i" after "n" is silent. "S" is pronounced as /s/ and the "o" is pronounced as /ə/ converting "son" to "suh-n". Therefore, the correct pronunciation is "too-nee-suh-n". Paying attention to the IPA phonetic transcription can help in spelling and pronouncing the word correctly.