The correct spelling of the word is "tighten", which is pronounced as /ˈtaɪtn/. The "gh" spelling in words such as "tight" and "night" is a remnant of Old English, where it was pronounced as a guttural fricative sound. However, over time, the pronunciation has changed to a simple "t" sound. Therefore, the correct spelling of this word is with a "t" and not a "gh". It is essential to use correct spelling in written communication to convey the intended message accurately.