Is XML a language or a data format?

Hi Folks,

Yesterday a colleague made a fascinating distinction between “language” and “data format”:

First he noted that English is a language, not a data format. Likewise, Java is a language, not a data format.
A language is specified by a grammar. There is a grammar for English and a grammar for Java. A language is intended to read by humans.
A data format probably does not have a grammar. It oftentimes is simply a collection of pieces and parts. It is intended to be processed by a machine. An example of a data format is JPEG (Exif). There is no grammar for it. It is just a series of parts pieced together as the graphic below illustrates.

Do you agree with that distinction? How do you define language? How do you define data format? How do they differ?

There is an XML grammar. XML is intended to be read by humans. Therefore, XML is a language. Right?

On the other hand, XML is a format for structuring data. XML is intended to be processed by machines. Therefore, XML is a data format. Right?

Which is it, a language or a data format?

/Roger