Especially if you're researching your family history, it can be fascinating to read their old letters. But often, the old handwriting can be impossible to read - and that's if you read German at all!
In the United States, handwriting hasn't changed much in the last 100 years. But in Germany, the script used in handwriting has changed dramatically. Letters from your ancestors can be impossible to read because of these changes in script. In order to translate handwritten German to English, you need substantial experience in understanding the old scripts