TH German and T English. the h is silent in German in words like this:
Thaler -taler -dollar
Theresa -Teresa
Otello -Othello ! The opera Otello by Verdi is Italian, also called Otello in German, but Othello in English, based on the Shakespeare play about a Moorish general in Venice.

Often suggested that it is a form of Otto. Shakespeare didn't confide in me, so I dunno.