An extra note:
There are many English words which have a very weak vowel sound, which is a bit like the short /ŭ/ sound.
Read these words aloud and listen to the sound of the vowel in the second syllable:
The sound in each case is rather like a soft /ŭ/ sound. This sound is called the 'schwa' (say 'shwar' to rhyme with car. ) The word 'schwa' is German, but it comes originally from the Hebrew word meaning 'emptiness' - because it often sounds as if there is no vowel there at all.
As you can see from the words above, different vowels are used to spell the schwa sound. There are no rules to tell you which vowel to use: you just have to remember what each word looks like.
Some more examples:
To learn more about the schwa sound, have a look at Unit 24
This completes the unit on spelling the short vowel sounds