It much more informal than "delighted" or "happy", and it's not really something a man would say - probably more a woman. A lot of the time it is used in a humorous way.

First notebook entry: Introducing myself

Dear all, (Sirs is very formal)

I would like to introduce myself.
My name is Vadeem. I am currently working in an international company so I need to improve my language skills.
In my everyday life I use technical and business language.

They all have the same meaning, and can be used interchangeably - they are all essentially the same. "You broke that vase intentionally" "You broke that vase deliberately" "You broke that vase on purpose"

Just a person's preference, there is no difference. I think "twelve hundred" is used more in the USA than in the UK.

In the UK, a biscuit can be any type or brand. A cookie is a specific type of biscuit, the stereotypical flat American type with (or without) chocolate chips. In the US, a cookie is any type or brand - they use "cookie" as the British use "biscuit".

They can be used to seek information, it just tends to be after the topic has already been introduced. You wouldn't use these phrases to ask a question initially, however if you continued asking then these can be used. They are, essentially, making suggestions but still getting more information. For example: A - "Do you like carrots? B- "Not really" A - "What about peas?" They can also be used to make a suggestion. For example: "What time would you like to go out. How about 9pm?"