I'm currently trying to place a validation rule on a text field which is supposed to contain several English words as well as numbers and no other languages or characters. I've tried setting the validation rule as:

Code:
Is Null or Not Like "*[!a-z]*"    
Is Null or Not Like "*[!a-z0-9]*"
Is Null or Not Like "*[!a-z]*" Or Not Like "*[!0-9]*"



Which results in limiting the field to a either a null or a single word. As the field requires several words and numbers none of those solutions were appropriate. I've also tried simply removing the asterisk at the beginning of the block:

Code:
Is Null or Not Like "[!a-z]*"
Is Null or Not Like "[!a-z0-9]*
This produces a result that is very close to what I need. However, some foreign (primarily Chinese) characters are showing up in the fields when data is imported.
Is there a reliable way to limit a field to only English words with numbers?