digraphs in German

Check this: http://blaoism.blogspot.com/2012/11/why-reuters-is-pronounced-way-it-is.html

au: Audi, Faust(ian), Strauss, Gauss, Schopenhauer, sauerkraut, meerschaum, Schaum (books), Braun, umlaut, ablaut
eu: Freud, Deutsch, Reuters, Schandenfreude, Creutzfeldt-Jakob disease
ei: Heineken, Heinz, Reinhardt, Weizmann
ey: Altzay, Bristol-Meyers
ai: Kaiser
ay: Bayreuth (a city name)
ie: Siemens

From wiki:

• au: [aʊ]
• eu and äu: [ɔʏ]
• ei, ai, ey, and ay: [aɪ]

Long vowels: < VV >, < Vh >, < CC >

http://joycep.myweb.port.ac.uk/pronounce/vowlong.html