The correct spelling of the word "tonis" is actually "tonnes" in British English or "tons" in American English. The pronunciation of "tonnes" is /tʌnz/, with the stress on the first syllable. The spelling with a double "n" indicates the plural form of "ton", a unit of weight equivalent to 1,000 kilograms or 2,204 pounds. It's important to use the correct spelling in order to avoid confusion when communicating quantities in metric or imperial measurements.