LTS, even an excellent command of English is insufficient when it comes to call centres. For them to be effective, you also need

- to be easily understood by your target audience (have you noticed how those Glasgow accents have softened recently?)
- to be more than a little knowledgeable about the subject they handle so as to be helpful; and that means very often to have sufficient knowledge of the context in which some questions are answered

Both of the above are sadly lacking in outsourced call centres.