I’m going to explain something for a minute here, feel free to ignore this.
If you’re writing a character with an accent, and you decide to include the visual pronunciation of the accent, that’s fine. If you decide to do this though, make sure you know what you’re doing. I’m going to write this for German and Italian, because those are the two that I find are miswritten most often.
ITALIAN: Italian is a rather musical pronunciation, soft sounds and stresses. Words ending in consonants have a small lifted vowel added, usually a or o. If you’re writing this into text, make sure you consider where. Don’t write it to every word, that makes it difficult to read. Don’t add a vowel to words already ending in a vowel sound. (This includes silent e’s- it’s a much less obvious stress , more a release of the consonant than an addition of a vowel, and doesn’t need to be added) Don’t add to words directly preceding a starting vowel; the words will blend slightly by themselves, adding the leading vowel to the pronunciation of the previous word.
GERMAN: German-accented text is usually full of v’s, j’s, and z’s. While this is evident in speech, it’s not usually so obvious, unless the character speaks little English. Leading y sounds are frequently changed to j- but keep in mind this is usually a very soft change, and not noticeable in many places. W to v really can’t be avoided, but consider the fact that your character is aware of their accent and mispronunciation, and try to keep w words to a minimum. The other big change is th to z, but this should only be written in characters with a very heavy accent, most of the time it’s just a clipped roll of the t rather than a full change, and please don’t do this in the middle of a word.
Try to keep in mind ease of reading, and you should actually listen to someone with the accent you’re writing before you try to document it.