When typing German, if umlaut letters are not available, it is usual to replace them with the underlying vowel followed by an ⟨e⟩. So, for example, "Schröder" becomes "Schroeder".
I would like to ask, if there are some words in the German language that contain the combinations "ae", "oe", or "ue" before any umlaut substitution?
In other words, if I encounter a word containing "ae", "oe", or "ue", can I be sure that the correct way to write the word is with the appropriate umlaut?
The reason is that I have a large body of text, where these substitutions were used and I need to convert it back to the original. I am considering just writing a script that would replace each occurrence of "ae", "oe", or "ue" (taking capitalization into account) with the relevant umlaut letter, but I am not sure if this is correct.