An umlaut is represented by two horizontal dots at the top of a vowel sound. The umlaut notation is used to signal a raised vowel sound in Germanic languages. If you are typing in German, Old English or another language using umlauts, a standard American keyboard doesn't have a built-in key for this character. However, your computer is equipped with command sequences for inserting umlauts from a regular keyboard.
Click on the place in your text where you want to insert a vowel with an umlaut.
Turn on your computer's "NumLock" button.
Hold down the "Alt" key.
Type the appropriate code into your computer's 10-key pad. The code varies based on the vowel that you want the umlaut over, and whether it is capitalised or not. The umlaut codes for each vowel are as follows: A=0196, E=0203, I=0207, O=0214, U=0220, Y=0159, a=0228, e=0235, i=0239, o=0246 u=0252, y=0255.
Let go of the "Alt" key once you finish entering the code. The selected vowel appears on your screen with an umlaut over it.