Correct spelling for the English word "sitton" is [sˈɪtən], [sˈɪtən], [s_ˈɪ_t_ə_n] (IPA phonetic alphabet).
There isn't a specific word sitton in English. It might be a misspelling or a regional pronunciation of the word sitting. Sitting is the present participle form of the verb sit. The word sit originated from the Old English word sittan, which can be traced back to the Proto-Germanic word sitjanan.