Correct spelling for the English word "wirth" is [wˈɜːθ], [wˈɜːθ], [w_ˈɜː_θ] (IPA phonetic alphabet).
The word wirth comes from the Old English word weorð, which means worth, value. Over time, it evolved into wyrth in Middle English and eventually became worth in Modern English. The word worth is used to describe the value or importance of something, and it can also be found in compounds such as unworthy or worthwhile.