German has two variants for ch, depending on whether the surrounding letters are ‘bright’ or ‘dark’.   If you say “ee, ey”  versus “o, oo, a

Ä, Ö and Ü are simple variations of familiar letters, but the ​​fourth letter that German has that we don’t is the real kicker:  ß  Eszett

Old German letters are tough to read but they are mostly the same alphabet we use - just with a few variations.